KR102211902B1 - Adhesive sheet and adhesive sheet peeling method - Google Patents

Abstract

An adhesive sheet having an adhesive layer is provided. The pressure-sensitive adhesive layer includes A layer constituting at least one surface of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet has an adhesive strength (N0) of 2.0 N/10 mm or more after one day at room temperature after affixing the layer A side to a surface having a contact angle of 5 to 10 degrees with respect to distilled water, of an alkali glass plate by a float method as an adherend. , After 1 day at room temperature, the decrease rate of the water resistance adhesion (N1) measured after immersing in water for 30 minutes and then wiping off the adherent water is 30% or less with respect to the adhesion (N0), and after 1 day at room temperature, 20 μL of distilled water was added dropwise to the adherend, and the distilled water was allowed to enter one end of the interface between the pressure-sensitive adhesive layer and the adherend, and then the water peeling force (N2) measured under conditions of a tensile speed of 300 mm/min and a peeling angle of 180 degrees. ) To the adhesive force (N0) is 40% or more.

Description

Adhesive sheet and adhesive sheet peeling method

The present invention relates to an adhesive sheet and an adhesive sheet peeling method. This application is for Japanese Patent Application No. 2018-018621 filed on February 5, 2018, Japanese Patent Application No. 2018-109385 filed on June 7, 2018, and Japanese Patent Application filed on July 31, 2018 The priority based on 2018-143420 is claimed, and the entire contents of these applications are taken in as a reference in this specification.

In general, the pressure-sensitive adhesive (also referred to as a pressure-sensitive adhesive. The same applies hereinafter) exhibits a soft solid (viscoelastic body) state in a temperature range near room temperature, and has a property of easily adhering to an adherend under pressure. Taking advantage of such properties, the pressure-sensitive adhesive is widely used in various fields in the form of a pressure-sensitive adhesive sheet with a support having an adhesive layer on the support, or in the form of a supportless pressure-sensitive adhesive sheet without a support.

Japanese Patent Application Publication No. 2005-148638

Various properties are required for the adhesive according to the application. Among these characteristics, it is difficult to achieve compatibility at a high level, such as a tendency for the other characteristics to deteriorate when an attempt is made to improve one characteristic. As an example of the characteristic in such a difficult relationship, adhesive force to an adherend and rework property are mentioned. The rework refers to a case in which an affixing error (location misalignment, occurrence of wrinkles or air bubbles, mixing of foreign substances, etc.) occurs when the adhesive sheet is affixed to the adherend, or when a problem is found in the adherend after the adhesive sheet is affixed. , It refers to peeling the adhesive sheet from the adherend and attaching it again. Patent Literature 1 discloses a technique of peeling the adhesive sheet from the substrate with good rework properties without damaging the substrate by peeling in a state in which a liquid is present at the peeling interface between the pressure-sensitive adhesive layer and the substrate (adherent). have. On the other hand, in Patent Literature 1, the effect of the liquid used when peeling the adhesive sheet from the substrate on the bonding reliability of the adhesive sheet in a phase where peeling is not intended is not examined.

Therefore, an object of the present invention is to provide a pressure-sensitive adhesive sheet that can be easily peeled off by using an aqueous liquid such as water and has good water resistance reliability. Another object of the present invention is to provide a method for peeling an adhesive sheet.

According to this specification, an adhesive sheet having an adhesive layer is provided. The pressure-sensitive adhesive layer includes A layer constituting at least one surface of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet has an adhesive strength (N0) after one day at room temperature after affixing the layer A side to a surface of an alkali glass plate produced by the float method as an adherend having a contact angle of 5 to 10 degrees with respect to distilled water (hereinafter, state) It is also called adhesive force (N0).) is 2.0 N/10 mm or more. Moreover, the said pressure-sensitive adhesive sheet has a water-resistant adhesive force reduction ratio of 30% or less, and a water peeling adhesive strength reduction ratio of 40% or more. Here, the water-resistant adhesive strength decrease rate is that the layer A side is affixed to the surface of the alkali glass plate produced by the float method as an adherend having a contact angle of 5 to 10 degrees with respect to distilled water, and 1 day at room temperature, immersed in water for 30 minutes, Then, from the water-resistant adhesion (N1) [N/10 ㎜] measured after wiping off the adherent water by pulling it up from the water, and from the above-described state adhesion (N0) [N/10 ㎜], the following equation: (1-(N1/N0 )) × 100; Is calculated by In addition, the water peeling adhesion reduction rate was 20 μL to the adherend after 1 day at room temperature after attaching the layer A side to the surface of the alkaline glass plate produced by the float method as an adherend having a contact angle of 5 to 10 degrees with respect to distilled water. Of distilled water was added dropwise, and the distilled water was allowed to enter one end of the interface between the pressure-sensitive adhesive layer and the adherend, and then in accordance with "10.4.1 Method 1: 180° peel adhesion to the test plate" of JIS Z0237:2009, specifically Is, water peeling force (N2) [N/10 mm] measured under conditions of a tensile speed of 300 mm/min and a peeling angle of 180 degrees using a tensile tester at a test temperature of 23° C., and the state adhesive force (N0) [N/ 10 mm], the following formula: (1-(N2/N0)) × 100; Is calculated by

The pressure-sensitive adhesive sheet can be easily peeled off using an aqueous liquid such as water, since the water peeling adhesive force decrease rate is 40% or more. And, in spite of the large decrease in adhesive strength due to water peeling in this way, since the water-resistant adhesive strength decrease rate is 30% or less, the water resistance reliability is excellent.

According to this specification, another pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer is also provided. The pressure-sensitive adhesive layer includes A layer constituting at least one surface of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet was affixed to the side of the layer A on the surface of the alkali glass plate produced by the float method as an adherend having a contact angle of 5 to 10 degrees with respect to distilled water, and 1 day at room temperature, immersed in water for 30 minutes, and then from water. Water-resistant adhesion (N1) [N/10 mm] measured after wiping off the adhered water by pulling it up, and adhesion (N0) [N/10 mm] after 1 day at room temperature after attaching the layer A side to the surface of the alkali glass plate From the following formula: (1-(N1/N0)) x 100; The water-resistant adhesive force reduction rate calculated by is 30% or less. In addition, the pressure-sensitive adhesive sheet has a dry peeling distance of 0.5 mm or less and a water entry distance of 10 mm or more in a static load peeling test described later.

The pressure-sensitive adhesive sheet exhibits good retention under dry peeling conditions, and can be easily peeled from the adherend by supplying an aqueous liquid such as water to the interface between the pressure-sensitive adhesive sheet and the adherend. And although it can be easily peeled off by using the aqueous liquid in this way, since the water-resistant adhesive strength decrease rate is 30% or less, the water resistance reliability is excellent.

In some embodiments, the layer A may be a layer formed from a water-dispersible pressure-sensitive adhesive composition (eg, an emulsion-type pressure-sensitive adhesive composition). According to such a layer A, it is easy to obtain a pressure-sensitive adhesive sheet showing a high water peel adhesion reduction rate.

In some embodiments, the layer B may be a layer formed from a photo-curable pressure-sensitive adhesive composition or a solvent-type pressure-sensitive adhesive composition. According to the pressure-sensitive adhesive layer including such a layer B, it is easy to obtain a pressure-sensitive adhesive sheet having a low water-resistance reduction rate and a high water-release adhesion reduction rate.

The layer A is preferably water-insoluble and non-water swellable. The pressure-sensitive adhesive sheet provided with such a layer A can be preferably peeled off from the adherend by effectively using a small amount of aqueous liquid. In addition, the adhesive sheet having good rework property is required to have a property that can be peeled off from the adherend without leaving the adhesive (non-swelling property).If the layer A is water-insoluble and non-water swellable, the pressure-sensitive adhesive constituting the layer A It is difficult to generate residuals for the complex.

In some embodiments, the layer A may contain a water affinity agent. According to the layer A containing a water affinity agent, it is easy to obtain a pressure-sensitive adhesive sheet which suitably achieves both water releasability and water resistance reliability. For example, a pressure-sensitive adhesive sheet that satisfies a water-resistance reduction rate of 30% or less and a water peeling adhesion decrease rate of 40% or more can be preferably realized. Further, by the use of a water affinity, for example, a pressure-sensitive adhesive sheet that satisfies a water-resistant adhesive strength reduction rate of 30% or less, a dry peeling distance of 0.5 mm or less, and a water entry distance of 10 mm or more can be preferably realized. The content of the water affinity agent may be, for example, 0.01 parts by weight or more and 20 parts by weight or less per 100 parts by weight of the monomer component constituting the polymer contained in the layer A.

In some aspects, the layer A can be constituted by an acrylic pressure-sensitive adhesive containing an acrylic polymer. The acrylic polymer is preferably a (meth)acrylate in which 50% by weight or more of the monomer component constituting the polymerized product has a hydrocarbon group having 1 to 20 carbon atoms at the ester terminal. The pressure-sensitive adhesive sheet disclosed herein can be preferably implemented in an aspect having the layer A having such a composition.

The thickness of the pressure-sensitive adhesive layer may be, for example, 10 μm or more and 200 μm or less. According to the pressure-sensitive adhesive layer having such a thickness, it is easy to achieve both a water-resistant adhesive strength reduction ratio of 30% or less and a water peeling adhesive strength reduction ratio of 40% or more. Moreover, according to the pressure-sensitive adhesive layer of such a thickness, it is easy to achieve both a water-resistant adhesive force reduction rate of 30% or less, a dry peeling distance of 0.5 mm or less, and a water entry distance of 10 mm or more.

Moreover, according to this specification, the adhesive sheet which has an adhesive layer is provided. The pressure-sensitive adhesive layer includes A layer constituting at least one surface of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer may further include a layer B disposed on the rear side of the layer A. As described above, according to the pressure-sensitive adhesive layer including the layer A and the layer B, for example, the layer A provides good water peelability, while the layer B provides bulk properties (e.g., water resistance, cohesiveness, heat resistance). Etc) can be adjusted. Therefore, according to the pressure-sensitive adhesive layer having such a constitution, for example, it is easy to obtain a pressure-sensitive adhesive sheet which suitably achieves both water peeling property and water resistance reliability. For example, a pressure-sensitive adhesive sheet having a high drop rate of water peeling adhesion and a low drop rate of water-resistant adhesion can be preferably realized. In addition, for example, a pressure-sensitive adhesive sheet having a long water entry distance and a low water-resistant adhesion reduction rate can be preferably realized. Thus, the configuration in which the pressure-sensitive adhesive layer includes the layer A and the layer B can be preferably employed, for example, in an aspect in which the thickness of the pressure-sensitive adhesive layer is more than 50 µm.

In an aspect in which the pressure-sensitive adhesive layer includes the layer A and the layer B, it is preferable that the layer B is disposed in direct contact with the rear surface of the layer A. The pressure-sensitive adhesive layer having such a configuration may be superior in followability to the surface shape (for example, a step) of the adherend compared to a configuration in which, for example, a non-adhesive intermediate layer is interposed between the layer A and the layer B. According to the pressure-sensitive adhesive sheet having such a pressure-sensitive adhesive layer, since the pressure-sensitive adhesive layer is easily adhered to the surface of an adherend, good water resistance is easily obtained.

In the aspect in which the pressure-sensitive adhesive layer includes the layer A and the layer B, the thickness of the layer B may be, for example, 20 μm or more. According to the layer B having such a thickness, the advantage of having the layer B on the back side of the layer A tends to be exhibited favorably.

In the aspect in which the pressure-sensitive adhesive layer includes the layer A and the layer B, the thickness of the layer A may be, for example, 5 μm or more and 50 μm or less. According to the layer A having such a thickness, it is easy to obtain a pressure-sensitive adhesive sheet which suitably achieves both water peeling property and water resistance reliability. For example, it is easy to obtain a pressure-sensitive adhesive sheet having a low water-resistant adhesive strength reduction rate and a high water peel adhesion reduction ratio (and/or a long water entry distance).

According to this specification, there is provided a pressure-sensitive adhesive sheet attachment member comprising a pressure-sensitive adhesive sheet disclosed herein and a member bonded to the one surface of the pressure-sensitive adhesive layer (that is, on the A-layer side). Such a member with a pressure-sensitive adhesive sheet may be, for example, a material having good rework properties when bonding the pressure-sensitive adhesive sheet to the member. For example, when a problem such as contamination of foreign substances occurs during the bonding, the pressure-sensitive adhesive sheet can be easily peeled off from the member and reattached using an aqueous liquid such as water. In addition, the adhesive sheet attachment member can have good reworkability using an aqueous liquid as described above, and also have good water resistance.

According to this specification, a method of peeling the pressure-sensitive adhesive sheet attached to the adherend from the adherend is provided. The method includes, in a state in which an aqueous liquid is present at the interface between the adherend and the pressure-sensitive adhesive sheet in a peeling wire of the pressure-sensitive adhesive sheet from the adherend, following the movement of the peeling wire, and the aqueous liquid It may include a water peeling process of peeling the pressure-sensitive adhesive sheet from the adherend while advancing the entry to the interface of. Here, the peeling wire refers to a point at which the adhesive sheet starts to fall off from the adherend when the peeling of the adhesive sheet from the adherend is advanced. According to the water peeling step, the adhesive sheet can be peeled from the adherend by effectively using the aqueous liquid. The adhesive sheet to be peeled off by applying the peeling method disclosed herein typically includes an adhesive layer. The adhesive sheet may be, for example, any adhesive sheet disclosed herein. In some aspects, it is preferable that the layer A constituting at least the surface on the side of the adherend among the pressure-sensitive adhesive layers is made of a pressure-sensitive adhesive containing a water affinity agent.

The peeling method may be preferably carried out in the aspect of moving the peeling wire at a speed of 10 mm/min or more in the water peeling process. According to this aspect, the adhesive sheet can be efficiently peeled off from the adherend.

1 is a cross-sectional view schematically showing a configuration of an adhesive sheet according to an embodiment.
2 is a cross-sectional view schematically showing a configuration of an adhesive sheet according to another embodiment.
3 is a cross-sectional view schematically showing a member with an adhesive sheet in which the adhesive sheet according to another embodiment is affixed to the member.
4 is a schematic explanatory view showing a method of measuring a dry peeling distance and a water entry distance.

Hereinafter, preferred embodiments of the present invention will be described. In addition, matters other than matters specifically mentioned in the present specification, matters necessary for carrying out the present invention, may be understood by those skilled in the art based on the teachings for carrying out the invention described in the present specification and common technical knowledge at the time of filing. The present invention can be implemented based on the content disclosed in this specification and the common technical knowledge in the field. In the following drawings, members and parts exhibiting the same action may be described with the same reference numerals, and overlapping descriptions may be omitted or simplified. In addition, the embodiment described in the drawings is schematically designed to clearly explain the present invention, and does not necessarily accurately represent the size or scale of a product that is actually provided.

In this specification, the "acrylic polymer" refers to a polymer derived from a monomer component containing more than 50% by weight of an acrylic monomer. The acrylic monomer refers to a monomer derived from a monomer having at least one (meth)acryloyl group in one molecule. In addition, in this specification, "(meth)acryloyl" means that acryloyl and methacryloyl are indicated comprehensively. Similarly, "(meth)acrylate" refers to an acrylate and a methacrylate, and "(meth)acryl" refers to an acrylic and methacrylic, respectively.

<Configuration example of adhesive sheet>

One configuration example of the pressure-sensitive adhesive sheet disclosed here is shown in FIG. 1. This pressure-sensitive adhesive sheet 1 includes a pressure-sensitive adhesive layer 10 in which one surface 10A is an affixing surface to an adherend, and a support 20 laminated on the other surface 10B of the pressure-sensitive adhesive layer 10 It is comprised as a single-sided adhesive pressure-sensitive adhesive sheet containing. The pressure-sensitive adhesive layer 10 is fixedly bonded to one surface 20A of the support 20. As the support 20, a plastic film such as a polyester film can be used, for example. In the example shown in FIG. 1, the pressure-sensitive adhesive layer 10 has a single layer structure. That is, the whole of the pressure-sensitive adhesive layer 10 is constituted by the layer A constituting one surface (adhesive surface) 10A of the pressure-sensitive adhesive layer 10. The pressure-sensitive adhesive sheet 1 before use (before affixing to the adherend) is, for example, as shown in FIG. 1, in which the pressure-sensitive adhesive surface 10A is at least the pressure-sensitive adhesive layer side as a releasable surface (release surface). It may be in the form of a pressure-sensitive adhesive sheet 50 with a release liner, protected with a release liner 30. Alternatively, the second surface 20B of the support 20 (a surface opposite to the first surface 20A, and also referred to as a rear surface) is a peeling surface, and an adhesion surface 10A on the second surface 20B ) May be a form in which the adhesive surface 10A is protected by being wound or laminated so as to abut.

The release liner is not particularly limited, and for example, a release liner in which the surface of a liner substrate such as a resin film or paper is peeled off, a fluorine-based polymer (polytetrafluoroethylene, etc.) or a polyolefin-based resin (polyethylene, polypropylene) Etc.), a release liner made of a low-adhesion material, etc. can be used. For the peeling treatment, for example, a release treatment agent such as a silicone type or a long chain alkyl type may be used. In some aspects, a resin film subjected to a release treatment can be preferably employed as a release liner.

Another configuration example of the pressure-sensitive adhesive sheet disclosed here is shown in FIG. 2. This pressure-sensitive adhesive sheet 2 includes a pressure-sensitive adhesive layer 110 in which one surface 110A is an affixing surface to an adherend, and a support 20 laminated on the other surface of the pressure-sensitive adhesive layer 110 It is comprised as a single-sided adhesive adhesive sheet. The pressure-sensitive adhesive layer 110 has a two-layer structure consisting of a layer A 112 constituting one surface (adhesive surface) 110A, and a layer B 114 laminated and disposed on the rear side of the layer A 112 Have. The pressure-sensitive adhesive sheet 2 before use (before affixing to the adherend) is the same as the pressure-sensitive adhesive sheet 1 shown in FIG. 1, wherein the pressure-sensitive adhesive surface 110A is protected with a release liner (not shown). It may be in the form of a sheet. Alternatively, the second surface 20B of the support 20 may be a peeling surface, and the adhesive surface 110A may be protected by winding or laminating so that the adhesion surface 110A abuts the second surface 20B. .

The pressure-sensitive adhesive sheet disclosed herein may be an aspect of a support-less double-sided pressure-sensitive adhesive sheet comprising an adhesive layer. Such a support-less double-sided adhesive sheet may be used by bonding a support to the other surface of the adhesive layer, for example.

The pressure-sensitive adhesive sheet disclosed herein may be a component of a member with a pressure-sensitive adhesive sheet in which a member is bonded to one surface of the pressure-sensitive adhesive layer (that is, the surface of the layer A). For example, the pressure-sensitive adhesive sheet 2 shown in FIG. 2 is, as shown in FIG. 3, of the pressure-sensitive adhesive sheet attachment member 200 to which the member 70 is bonded to one surface 110A of the pressure-sensitive adhesive layer 110 It can be a component. Instead of the adhesive sheet 2 shown in FIG. 2, you may use the adhesive sheet 1 shown in FIG. 1. As the member, it is preferable that the surface on which the pressure-sensitive adhesive sheet is affixed is a non-absorbent smooth surface. When attaching the adhesive sheet to the member, the member with a pressure-sensitive adhesive sheet having such a configuration can be easily reworked by applying a water peeling method described later as necessary. The member may be, for example, a glass substrate, a resin film, a metal plate, or the like. Suitable examples of the member include an optical member described later. Moreover, as for the said member, the surface to be bonded with an adhesive sheet may be hydrophilized. Examples of the hydrophilic treatment include treatments that contribute to the improvement of hydrophilicity, such as corona treatment, plasma treatment, and hydrophilic coating treatment for forming a hydrophilic coating layer.

<Characteristics of adhesive sheet>

The pressure-sensitive adhesive sheet provided by this specification has the characteristic that the water-resistant adhesive force decrease rate is 30% or less.

In a preferred aspect, the pressure-sensitive adhesive sheet has a water peeling adhesive force reduction ratio of 40% or more. According to this specification, a pressure-sensitive adhesive sheet having a water-resistance reduction rate of 30% or less and a water peeling adhesion decrease rate of 40% or more is provided.

In another preferred aspect, the pressure-sensitive adhesive sheet has a dry peeling distance of 0.5 mm or less and a water entry distance of 10 mm or more. According to this specification, there is provided a pressure-sensitive adhesive sheet having a water-resistant adhesion reduction rate of 30% or less, a dry peeling distance of 0.5 mm or less, and a water entry distance of 10 mm or more.

The water-resistant adhesive force reduction rate [%] is defined as a value calculated by (1-(N1/N0)) × 100 from the state adhesive force (N0) [N/10 mm] and the water-resistant adhesive force (N1) [N/10 mm]. do. The water peeling adhesive force reduction rate [%] is defined as a value calculated by (1-(N2/N0)) × 100 from the state adhesive force (N0) [N/10 mm] and the water peel force (N2). State adhesive force (N0), water resistant adhesive force (N1), and water peeling force (N2) are measured by the method described above, in detail, by the following method. The same measurement method is also used in Examples described later.

[Measurement of state adhesion (N0)]

The pressure-sensitive adhesive sheet to be measured is cut into a rectangle having a width of 10 mm and a length of 120 mm to prepare a test piece. A sample for evaluation in which the layer A side of the test piece was bonded to an adherend with a hand roller was put into an autoclave and treated for 15 minutes at a pressure of 5 atm and a temperature of 50°C.

After holding the sample for evaluation taken out from the autoclave in an environment of 23°C and 50% RH for 1 day, a cutter knife was inserted into the interface between the test piece and the adherend under the same environment, and one end in the longitudinal direction of the test piece was removed from the adherend. After peeling, according to "10.4.1 Method 1: 180° peel adhesion to test plate" of JIS Z0237:2009, specifically, using a tensile tester at a test temperature of 23°C, a tensile speed of 300 mm/min, a peel angle of 180 The peel strength was measured under the conditions of the figure.

[Measurement of water resistance adhesion (N1)]

The pressure-sensitive adhesive sheet to be measured is cut into a rectangle having a width of 10 mm and a length of 120 mm to prepare a test piece. A sample for evaluation in which the layer A side of the test piece was bonded to an adherend with a hand roller was put into an autoclave and treated for 15 minutes at a pressure of 5 atm and a temperature of 50°C.

The sample for evaluation taken out from the autoclave is maintained in an environment of 23°C and 50% RH for 1 day, and then immersed in water at room temperature (23°C to 25°C) for 30 minutes. As water, ion-exchanged water or distilled water is used. In water, the sample for evaluation is held horizontally in a direction in which the surface on which the test piece is affixed is upward. The distance (immersion depth) of the sample for evaluation from the upper surface to the water surface is 10 mm or more (for example, about 10 mm to 100 mm). Next, the sample for evaluation is pulled up from the water, and after carefully wiping off the water adhering to the sample for evaluation, a cutter knife is inserted into the interface between the test piece and the adherend to peel off one end of the test piece in the longitudinal direction, In an environment of 23°C and 50% RH, according to JIS Z0237:2009 “10.4.1 Method 1: 180° peel adhesion to test plate”, specifically, a tensile rate using a tensile tester at a test temperature of 23°C The peel strength was measured under conditions of 300 mm/min and a peel angle of 180 degrees. The time from pulling up the sample for evaluation from water until the peel strength is measured is set to within 10 minutes.

[Measurement of water peeling force (N2)]

The pressure-sensitive adhesive sheet to be measured is cut into a rectangle having a width of 10 mm and a length of 120 mm to prepare a test piece. A sample for evaluation in which the layer A side of the test piece was bonded to an adherend with a hand roller was put into an autoclave and treated for 15 minutes at a pressure of 5 atm and a temperature of 50°C.

After holding the sample for evaluation taken out of the autoclave in an environment of 23° C. and 50% RH for 1 day, 20 μL of distilled water was added to the surface of the adherend exposed from the one end in the longitudinal direction under the same environment. Dripping. Then, after inserting a cutter knife into the interface between the test piece and the adherend to allow the water to enter the interface, in accordance with "10.4.1 Method 1: 180° peel adhesion to the test plate" of JIS Z0237:2009, specifically , Peel strength was measured under conditions of a tensile speed of 300 mm/min and a peel angle of 180 degrees using a tensile tester at a test temperature of 23°C. In addition, water used in the measurement of the water peeling force (N2) is only 20 µL of distilled water that is dropped onto the adherend before the start of peeling.

The dry peeling distance and the water entry distance are measured by the following static load peeling test. The same measurement method is also used in Examples described later.

[Static load peeling test]

The pressure-sensitive adhesive sheet to be measured is cut into a rectangle having a width of 10 mm and a length of 150 mm to prepare a test piece. The side of the layer A of the test piece is bonded with a hand roller to a surface of an alkali glass plate produced by the float method as an adherend having a contact angle of 5 to 10 degrees with respect to distilled water to obtain a sample for evaluation. This sample for evaluation is put into an autoclave, and it processes for 15 minutes under the conditions of a pressure of 5 atm and a temperature of 50°C. After holding the sample for evaluation taken out from the autoclave in an environment of 23°C and 50% RH for 1 day, under the same environment, a range of 50 mm from one end in the longitudinal direction of the test piece was peeled off from the adherend to form a free end, and The adherend is fixed horizontally by opening the side on which the test piece is affixed downward. Next, a 100 g weight is fixed to the free end of the test piece, and 1 minute after the weight is fixed, 20 μL of distilled water is supplied to the interface between the test piece and the adherend. The weight is fixed to the free end, and the distance at which the peeling of the test piece has progressed from the adherend of the test piece for 1 minute after 0 seconds is measured, and it is set as the dry peeling distance. Distilled water is supplied to the interface and the distance at which the peeling has progressed from 0 seconds to 10 seconds is measured to be the water entry distance.

4 is a schematic explanatory view showing a method of measuring a dry peeling distance and a water entry distance. As described above, on the surface 80A of the alkali glass plate (adherent) 80 produced by the float method having a contact angle of 5 to 10 degrees with respect to distilled water, the A layer side of the test piece 82, that is, the adhesion surface ( 82A) is bonded together to obtain a sample for evaluation, and after treating this with an autoclave, the alkali glass plate 80 is held horizontally with the surface 80A downward. 50 mm from the one end 822 of the test piece 82 is peeled off from the alkali glass plate 80 to be a free end, and a 100 g weight 84 is fixed thereto, and the test piece during 1 minute from 0 seconds to 1 minute later The distance at which peeling from the alkali glass plate 80 of (82) progressed is measured, and this is made into the dry peeling distance (Dd) [mm]. When progress of peeling is not observed during the said 1 minute, the dry peeling distance Dd becomes 0 mm. One minute after fixing the weight 84 to one end 822 of the test piece 82, 20 μL of distilled water (W) was added to the interface between the test piece 82 and the alkali glass plate 80, for example, a microsyringe ( 86) supplied by. It is preferable that the supply position of the distilled water W is set to the center of the width of the test piece 82 in the interface (that is, the point at which the adhesive surface 82A starts to be separated from the surface 80A). Distilled water (W) is supplied to the interface, and the distance at which peeling has progressed from 0 seconds to 10 seconds later is measured, and this is taken as the water entry distance (Dw) [mm]. In addition, in FIG. 4, the state after 0 second after supplying the distilled water (W) to the said interface is indicated by a solid line, and the state after 10 seconds from supply of the said distilled water (W) is indicated by a virtual line.

In the measurement of the above-described state adhesive force (N0), water-resistant adhesive force (N1) and water peeling force (N2), and the dry peeling distance and water entry distance, as an adherend, as an alkali glass plate produced by the float method, a test piece The contact angle of the surface to be bonded to the distilled water is 5 to 10 degrees. For example, an alkali glass plate (thickness 1.35 mm, a blue plate polishing product) or an equivalent product thereof manufactured by Matsunami Glass Industry Co., Ltd. can be used as an adherend. The affixing of the test piece to the adherend is performed so that the distance from the outer circumferential end of the test piece to the outer circumferential end of the adherend is at least 10 mm or more, preferably 15 mm or more. In the pressure-sensitive adhesive sheet including a photo-crosslinkable pressure-sensitive adhesive layer, light irradiation is performed on the sample taken out from the autoclave through the alkali glass plate in an environment of 23°C and 50% RH, and then the peel strength is measured. The conditions of light irradiation (wavelength, irradiation intensity, irradiation time, etc.) may be appropriately set according to the composition or thickness of the pressure-sensitive adhesive layer. Moreover, as a tensile testing machine, a universal tensile-compression testing machine (equipment name "tensile compression testing machine, TCM-1kNB" manufactured by Minevea Corporation) or its equivalent can be used. The measurement of the peel strength is carried out so that the peeling of the test piece attached to the adherend proceeds from the bottom to the top. In the measurement, the test piece can be reinforced by attaching a suitable backing material to the back surface of the pressure-sensitive adhesive sheet (the surface opposite to the surface of the layer A) as necessary. As the backing material, for example, a polyethylene terephthalate film having a thickness of about 25 µm can be used.

In addition, the contact angle of the alkali glass plate is measured as follows. That is, in an environment of a measurement atmosphere of 23°C and 50% RH, a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd., brand name “DMo-501 type”, control box “DMC-2”, control/analysis software “FAMAS (version 5.0. 30)"), and measure by the droplet method. The dropping amount of distilled water is set to 2 µL, and the contact angle is calculated by the Θ/2 method from the image 5 seconds after the dropping (implemented with N5).

(Water peeling adhesion reduction rate)

It is preferable that the pressure-sensitive adhesive sheet disclosed here has a water peeling adhesive force reduction ratio of 40% or more. The pressure-sensitive adhesive sheet having a large value of the water peeling adhesive force reduction rate can be easily peeled using an aqueous liquid such as water. For example, a small amount of aqueous liquid is supplied to the adherend to which the pressure-sensitive adhesive sheet is affixed, and the aqueous liquid enters the interface between the pressure-sensitive adhesive sheet and the adherend from one end of the pressure-sensitive adhesive sheet to create an instrument for peeling, and then the pressure-sensitive adhesive sheet By peeling, the peeling strength of the pressure-sensitive adhesive sheet from the adherend can be significantly reduced. By using this property, it is possible to achieve both high adhesive strength and good rework properties in normal use. In some aspects, the water peel adhesion reduction rate may be, for example, 50% or more, 65% or more, 75% or more, 85% or more, 90% or more, or 95% or more. And 97% or more may be sufficient. The water peeling adhesion reduction rate is 100% or less in principle, and is typically less than 100%.

(Dry peeling distance and water entry distance)

It is preferable that the adhesive sheet disclosed here satisfies a dry peeling distance of 0.5 mm or less and a water entry distance of 10 mm or more. Such a pressure-sensitive adhesive sheet can be easily applied under a condition where there is no liquid water at the interface between the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet and the adherend, that is, under dry peeling conditions, even if a force in the direction of peeling the pressure-sensitive adhesive sheet from the adherend is applied. It is excellent in the reliability of bonding because it does not peel and exhibits good retention. On the other hand, the adhesive sheet can be easily peeled from the adherend by supplying an aqueous liquid such as water to the interface between the adhesive sheet and the adherend. This is preferable from the viewpoint of reworkability and recycling property.

In some aspects, the dry peeling distance may be, for example, 0.4 mm or less, 0.3 mm or less, 0.2 mm or less, 0.1 mm or less, or less than 0.1 mm. Generally, the shorter the dry peeling distance is, the more preferable it is, and it is particularly preferable that it is substantially 0 mm. Here, substantially 0 mm means that the progress of peeling is not observed for 1 minute from 0 seconds after adding a weight to the free end of the test piece. Above all, in consideration of the balance with other properties, the pressure-sensitive adhesive sheet disclosed herein can be preferably implemented in an aspect in which, for example, a dry peeling distance is more than 0.1 mm or more than 0.2 mm.

In some aspects, the water entry distance may be, for example, 14 mm or more, 18 mm or more, or 20 mm or more. From the viewpoint of improving the water peelability of the pressure-sensitive adhesive sheet, it can be said that the longer the water entry distance is, the more preferable. In addition, the water entry distance does not exceed the length of the portion where the test piece is bonded to the adherend when distilled water is supplied to the interface between the test piece and the adherend in the static load peeling test. For example, when a test piece having a length of 150 mm is used and 50 mm from one end of the test piece is peeled from the adherend to form a free end and a weight is applied, it varies depending on the dry peel distance, but, for example, the dry peel distance When is 0 mm, the upper limit of the water entry distance is 100 mm. In addition, if the peeling proceeds to the end opposite to the one end of the test piece within 10 seconds after supplying distilled water and the test piece falls from the adherend, the water entry distance differs depending on the dry peeling distance. When the peeling distance is 0 mm, it can be evaluated as more than 100 mm.

(Reduction rate of water-resistant adhesion)

Although the pressure-sensitive adhesive sheet disclosed herein can be easily peeled off using an aqueous liquid such as water as described above, since the water-resistant adhesive strength decrease rate is 30% or less, it is excellent in water resistance reliability. From the viewpoint of obtaining higher water resistance reliability, the water-resistant adhesive strength reduction rate is preferably 20% or less, more preferably 10% or less, and may be 7% or less, for example. The water-resistant adhesion reduction rate is typically 0% or more. In the pressure-sensitive adhesive sheet disclosed herein, the difference between the water peel adhesion reduction rate [%] and the water-resistant adhesion reduction rate [%] is, for example, 45% or more, or 55% or more, or 70% or more, or 80% or more, or 90% It can be preferably carried out in the above mode.

It is preferable that the adhesive sheet disclosed here has a state adhesive force (N0) of 2.0 N/10 mm or more from the viewpoint of the reliability of bonding. In some aspects, the state adhesion (N0) may be, for example, 2.5 N/10 mm or more, 3.0 N/10 mm or more, 3.5 N/10 mm or more, or 4.0 N/10 mm or more. May be. The upper limit of the state adhesive force N0 is not particularly limited, and may be, for example, 30 N/10 mm or less. In some aspects, the state adhesive force (N0) may be 20 N/10 mm or less, or 15 N/10 mm or less.

The water peeling force (N2) is preferably 60% or less (more preferably 50% or less) of the state adhesive force N0. Although not particularly limited, the water peeling force (N2) may be, for example, 10 N/10 mm or less, 3.5 N/10 mm or less, 3.0 N/10 mm or less, and 2.5 N/10 mm or less It may be sufficient, 1.6 N/10 mm or less may be sufficient, 1.2 N/10 mm or less may be sufficient, and 1.0 N/10 mm or less may be sufficient. According to the adhesive sheet having a low water peeling force (N2), the load applied to the adherend when peeling the adhesive sheet can be reduced. This is particularly significant in a pressure-sensitive adhesive sheet adhered to, for example, a thin adherend, a fragile adherend, an adherend susceptible to deformation (elongation, warpage, twist, etc.), an adherend having a thin film that is susceptible to damage to the surface. The pressure-sensitive adhesive sheet disclosed herein is, for example, a water peeling force (N2) of 0.75 N/10 mm or less, or 0.50 N/10 mm or less, or 0.25 N/10 mm or less, or 0.15 N/10 mm or less. It can also be carried out preferably. The lower limit of the water peeling force (N2) is not particularly limited, and may be substantially 0 N/10 mm or more than 0 N/10 mm.

In addition, from the viewpoint of improving the rework property, in the measurement of the water peeling force (N2), a pressure-sensitive adhesive sheet which is peeled from the adherend without leaving the pressure-sensitive adhesive on the adherend is preferable. That is, a pressure-sensitive adhesive sheet having excellent wetness retention is preferable. The presence or absence of the adhesive on the adherend can be grasped, for example, by visually observing the adherend after peeling the adhesive sheet.

The ratio (N2/N0) of the water peeling force (N2) [N/10 mm] to the state adhesive force (N0) [N/10 mm] may be, for example, 1/2.5 or less, or 1/5 or less. , 1/10 or less may be sufficient. The smaller the ratio (N2/N0) means that the water peeling force (N2) is more markedly lowered with respect to the state adhesive force (N0). The pressure-sensitive adhesive sheet disclosed herein can be preferably implemented in an aspect in which the ratio (N2/N0) is 1/15 or less, 1/25 or less, or 1/35 or less. The upper limit of the ratio (N2/N0) is not particularly limited, and for example, it may be 1/200 or more, 1/150 or more, or 1/100 or more.

In the pressure-sensitive adhesive sheet disclosed here, it is preferable that the pressure-sensitive adhesive constituting the layer A constituting at least one surface of the pressure-sensitive adhesive layer is water-insoluble. According to the water-insoluble layer A, it is easy to obtain a pressure-sensitive adhesive sheet having a high water-resistant adhesion (N1) and a low water-resistant adhesion reduction rate. The fact that the layer A is water-insoluble is also preferable from the viewpoint of preventing a phenomenon in which the pressure-sensitive adhesive remains on the adherend during peeling using an aqueous liquid such as water. Further, the fact that the layer A is water-insoluble can be advantageous also from the viewpoint of preventing the phenomenon that the transparency of the pressure-sensitive adhesive sheet is lowered due to water immersion or moisture in the environment.

In the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive constituting the layer A is preferably non-water swellable. According to the non-water swellable layer A, it is easy to obtain a pressure-sensitive adhesive sheet having a high water-resistant adhesive force (N1) and a low water-resistant adhesive force reduction rate. Moreover, in peeling using an aqueous liquid such as water, good peelability can be exhibited by effectively using a small amount of aqueous liquid. The fact that the layer A is non-water swellable is also preferable from the viewpoint of preventing a phenomenon in which the pressure-sensitive adhesive remains on the adherend during peeling using an aqueous liquid. Further, the fact that the layer A is non-water swellable can be advantageous also from the viewpoint of preventing a phenomenon in which the transparency of the pressure-sensitive adhesive sheet is lowered due to water immersion or moisture in the environment.

Here, in this specification, the term "water-insoluble" of the pressure-sensitive adhesive means that the gel fraction measured by the following method is 75% or more. Moreover, that the adhesive is non-water swellable means that the swelling degree measured by the following method is 2 or less.

That is, about 0.5 g of the pressure-sensitive adhesive to be measured is weighed, and the weight is set to W1. After immersing this pressure-sensitive adhesive in 500 mL of distilled water at room temperature (about 23° C.) for 48 hours, it is filtered through a nylon mesh, and the weight W2 of the pressure-sensitive adhesive containing water is measured. After that, the pressure-sensitive adhesive is dried at 130° C. for 5 hours, and the weight W3 of the nonvolatile matter is measured. The gel fraction and swelling degree are calculated by the following equation.

Gel fraction [%] = (W3/W1) × 100

Swelling degree = W2/W1

In some aspects, the gel fraction of the layer A may be, for example, 80% or more, 90% or more, 95% or more, or 98% or more. In principle, the gel fraction of the layer A is 100% or less. Moreover, in some aspects, the swelling degree of the A layer may be 1.7 or less, 1.5 or less, and 1.2 or less, for example. The degree of swelling of the layer A is usually 1.0 or more, and typically exceeds 1.0.

In the pressure-sensitive adhesive sheet having a configuration in which the pressure-sensitive adhesive layer includes the layer A and the layer B disposed on the rear side of the layer A, the gel fraction of the layer B is not particularly limited. In some embodiments, the gel fraction of the layer B is preferably equal to or greater than the gel fraction of the layer A, and may be higher than the gel fraction of the layer A. The gel fraction of the layer B may be, for example, 90% or more, 95% or more, 98% or more, or 99% or more. In principle, the gel fraction of the layer B is 100% or less. Moreover, the gel fraction of the whole pressure-sensitive adhesive layer may be, for example, 85% or more, 90% or more, 95% or more, 98% or more, or 99% or more. In addition, in the pressure-sensitive adhesive layer composed of only layer A, the gel fraction of the entire pressure-sensitive adhesive layer means the gel fraction of the layer A.

In the pressure-sensitive adhesive sheet having a configuration in which the pressure-sensitive adhesive layer includes the layer A and the layer B disposed on the back side of the layer A, the degree of swelling of the layer B is not particularly limited. In some aspects, the degree of swelling of the layer B is preferably equal to or less than that of the layer A, and may be lower than the degree of swelling of the layer A. The degree of swelling of the layer B may be, for example, 1.5 or less, 1.3 or less, or 1.1 or less. The degree of swelling of the layer B is usually 1.0 or more, and typically exceeds 1.0. Moreover, the degree of swelling of the entire pressure-sensitive adhesive layer may be, for example, 1.6 or less, 1.4 or less, 1.2 or less, and 1.1 or less. In addition, in the pressure-sensitive adhesive layer composed of only layer A, the degree of swelling of the entire pressure-sensitive adhesive layer means the degree of swelling of the layer A.

In addition, the gel fraction and the degree of swelling of the pressure-sensitive adhesive with respect to water can be determined by appropriately employing common techniques for those skilled in the art at the time of filing this application, such as the composition of the monomer component, the weight average molecular weight of the polymer, the use of a crosslinking agent or a polyfunctional monomer Can be adjusted.

<Adhesive layer>

(1) A layer

In the pressure-sensitive adhesive sheet disclosed herein, the layer A constituting at least one surface of the pressure-sensitive adhesive layer is, for example, an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive (natural rubber, synthetic rubber, mixtures thereof, etc.), a silicone pressure-sensitive adhesive, and poly It may be a pressure-sensitive adhesive layer comprising one or two or more pressure-sensitive adhesives selected from various known pressure-sensitive adhesives such as ester-based pressure-sensitive adhesive, urethane-based pressure-sensitive adhesive, polyether-based pressure-sensitive adhesive, polyamide-based pressure-sensitive adhesive, and fluorine-based pressure-sensitive adhesive. Here, the acrylic pressure-sensitive adhesive refers to a pressure-sensitive adhesive containing an acrylic polymer as a main component. It has the same meaning for rubber-based adhesives and other adhesives. In addition, the concept of the polymerized product here also includes a polymer having a relatively low polymerization degree that may be generally referred to as an oligomer.

(Acrylic adhesive)

From the viewpoints of transparency and weather resistance, in some aspects, an acrylic pressure-sensitive adhesive can be preferably employed as a constituent material of the layer A.

As an acrylic adhesive, for example, an acrylic polymer composed of a monomer component containing more than 50% by weight of an alkyl (meth)acrylate having a linear or branched alkyl group having 1 to 20 carbon atoms at the end of the ester. It is preferable to include. Hereinafter, the (meth)acrylic acid alkyl ester having an alkyl group having X or more and Y or less in the ester terminal may be referred to as "(meth)acrylic acid C _XY alkyl ester". From the point that it is easy to balance the properties, the proportion of the (meth)acrylic acid C _1-20 alkyl ester in the whole monomer component may be, for example, 55% by weight or more, 60% by weight or more, or 70% by weight or more. . For the same reason, the proportion of the (meth)acrylic acid C _1-20 alkyl ester in the monomer component may be, for example, 99.9% by weight or less, 99.5% by weight or less, or 99% by weight or less.

Non-limiting specific examples of the (meth)acrylic acid C _1-20 alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, and n- (meth)acrylate. Butyl, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, Octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isoctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, ( Undecyl meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, (meth)acrylate ) Stearyl acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, and the like.

Among these, it is preferable to use at least (meth)acrylic acid C _4-20 alkyl ester, and it is more preferable to use at least (meth)acrylic acid C _4-18 alkyl ester. For example, an acrylic pressure-sensitive adhesive containing one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) as the monomer component is preferred, and an acrylic pressure-sensitive adhesive containing at least 2EHA is particularly preferred. Other examples of (meth)acrylic acid C _4-20 alkyl esters that can be preferably used include isononyl acrylate, n-butyl methacrylate (BMA), 2-ethylhexyl methacrylate (2EHMA), isostearyl acrylate (ISTA), etc. are mentioned.

In some embodiments, the monomer component constituting the acrylic polymer may contain (meth)acrylic acid C _4-18 alkyl ester in a proportion of 40% by weight or more. As described above, according to the monomer component containing a relatively large amount of an alkyl (meth)acrylate having an alkyl group having 4 or more carbon atoms at the ester terminal, an acrylic polymer having high lipophilicity tends to be formed. According to the acrylic polymer having a high lipophilicity, the pressure-sensitive adhesive layer having a low water-resistant adhesion reduction rate is likely to be formed. The proportion of the (meth)acrylic acid C _4-18 alkyl ester in the monomer component may be, for example, 60% by weight or more, 70% by weight or more, 75% by weight or more, or 80% by weight or more. It may be a monomer component containing a (meth)acrylic acid C _6-18 alkyl ester in a ratio equal to or more than any of the lower limits described above.

In addition, from the viewpoint of increasing the cohesiveness of the pressure-sensitive adhesive layer and preventing cohesive failure, the proportion of the (meth)acrylic acid C _4-18 alkyl ester in the monomer component is usually 99.5% by weight or less, and 99% by weight or less. It may be sufficient, 98 weight% or less may be sufficient, and 97 weight% or less may be sufficient. It may be a monomer component containing a (meth)acrylic acid C _6-18 alkyl ester in the ratio below any upper limit mentioned above.

The monomer component constituting the acrylic polymer may contain other monomers (copolymerizable monomers) which can be copolymerized with the (meth)acrylate alkyl ester, if necessary, together with the (meth)acrylate alkyl ester. As the copolymerizable monomer, a monomer having a polar group (eg, a carboxyl group, a hydroxyl group, a nitrogen atom-containing ring, etc.) can be preferably used. The monomer having a polar group may be helpful in introducing a crosslinking point to the acrylic polymer or increasing the cohesive strength of the pressure-sensitive adhesive. Copolymerizable monomers can be used alone or in combination of two or more.

The following are mentioned as a non-limiting specific example of a copolymerizable monomer.

Carboxy group-containing monomer: For example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like.

Acid anhydride group-containing monomers: For example, maleic anhydride, itaconic anhydride.

Hydroxyl-containing monomer: For example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth)acrylate ) 4-hydroxybutyl acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, ( Hydroxyalkyl (meth)acrylates such as 4-hydroxymethylcyclohexyl)methyl (meth)acrylate;

Monomers containing a sulfonic acid group or a phosphoric acid group: For example, styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamide propanesulfonic acid, sulfopropyl (meth) Acrylate, (meth)acryloyloxynaphthalenesulfonic acid, 2-hydroxyethylacryloyl phosphate, and the like.

Epoxy group-containing monomers: For example, epoxy group-containing acrylates such as glycidyl (meth)acrylate and 2-ethylglycidyl ether (meth)acrylate, allyl glycidyl ether, glycidyl ether (meth)acrylate, etc. .

Cyano group-containing monomer: For example, acrylonitrile, methacrylonitrile, etc.

Isocyanate group-containing monomer: For example, 2-isocyanate ethyl (meth)acrylate, etc.

Amide group-containing monomer: For example, (meth)acrylamide; N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-dipropyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide, N, N,N-dialkyl (meth)acrylamide, such as N-di(n-butyl)(meth)acrylamide and N,N-di(t-butyl)(meth)acrylamide; N-alkyl (meth)acrylamides such as N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide, and N-n-butyl (meth)acrylamide; N-vinylcarboxylic acid amides, such as N-vinyl acetamide; Monomers having a hydroxyl group and an amide group, such as N-(2-hydroxyethyl)(meth)acrylamide, N-(2-hydroxypropyl)(meth)acrylamide, N-(1-hydroxypropyl) (Meth)acrylamide, N-(3-hydroxypropyl)(meth)acrylamide, N-(2-hydroxybutyl)(meth)acrylamide, N-(3-hydroxybutyl)(meth)acrylamide , N-hydroxyalkyl (meth)acrylamide, such as N-(4-hydroxybutyl)(meth)acrylamide; Monomers having an alkoxy group and an amide group, for example, N-alkoxyalkyl such as N-methoxymethyl (meth)acrylamide, N-methoxyethyl (meth)acrylamide, and N-butoxymethyl (meth)acrylamide (Meth)acrylamide; In addition, N,N-dimethylaminopropyl (meth)acrylamide, N-(meth)acryloylmorpholine, etc.

Amino group-containing monomer: For example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate.

Monomers having an epoxy group: For example, glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ether.

Monomers having a nitrogen atom-containing ring: For example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinyl Piperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloyl piperi Dean, N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazine-2 -One, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, N-vinylisothiazole, N-vinylpyridazine, etc. (e.g. , Lactams such as N-vinyl-2-caprolactam).

Monomers having a succinimide skeleton: For example, N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acrylic Royl-8-oxyhexamethylene succinimide, etc.

Maleimides: For example, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide, and the like.

Itaconimides: For example, N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itacone Mid, N-cyclohexyl itaconimide, N-lauryl itaconimide, etc.

Aminoalkyl (meth)acrylates: For example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, t- (meth)acrylate Butylaminoethyl.

Alkoxy group-containing monomer: For example, 2-methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, (meth) Alkoxyalkyl (meth)acrylates such as butoxyethyl acrylate and ethoxypropyl (meth)acrylate; Alkoxyalkylene glycols (meth)acrylates, such as methoxyethylene glycol (meth)acrylate and methoxypolypropylene glycol (meth)acrylate.

Alkoxysilyl group-containing monomer: For example, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3- (Meth)acryloxypropylmethyldiethoxysilane.

Vinyl esters: For example, vinyl acetate, vinyl propionate, etc.

Vinyl ethers: For example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.

Aromatic vinyl compounds: For example, styrene, α-methylstyrene, vinyltoluene, and the like.

Olefins: For example, ethylene, butadiene, isoprene, isobutylene, etc.

(Meth)acrylic acid ester having an alicyclic hydrocarbon group: For example, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, a Damantyl (meth)acrylate, etc.

(Meth)acrylic acid ester having an aromatic hydrocarbon group: For example, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, and the like.

In addition, heterocycle-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate, halogen atom-containing (meth)acrylates such as vinyl chloride or fluorine atom-containing (meth)acrylates, silicone (meth)acrylates (Meth)acrylic acid ester obtained from silicon atom-containing (meth)acrylate, terpene compound derivative alcohol, etc.;

In the case of using such a copolymerizable monomer, the amount of the copolymerizable monomer is not particularly limited, but it is usually appropriate to be 0.01% by weight or more of the total monomer component. From the viewpoint of better exhibiting the effect of using the copolymerizable monomer, the amount of the copolymerizable monomer may be 0.1% by weight or more of the total monomer component, or 0.5% by weight or more. In addition, from the viewpoint of facilitating balance of the adhesive properties, the amount of the copolymerizable monomer to be used is usually appropriately 50% by weight or less, preferably 40% by weight or less of the total monomer component.

In some aspects, it is preferable that the monomer component contains a carboxy group-containing monomer. As a suitable example of a carboxy group-containing monomer, acrylic acid (AA) and methacrylic acid (MAA) are mentioned. You may use AA and MAA together. When AA and MAA are used together, their weight ratio (AA/MAA) is not particularly limited, and can be, for example, in the range of approximately 0.1 to 10. In some aspects, the weight ratio (AA/MAA) may be, for example, approximately 0.3 or higher, or approximately 0.5 or higher. Moreover, the said weight ratio (AA/MAA) may be about 4 or less, and about 3 or less, for example.

By use of a carboxyl group-containing monomer, an aqueous liquid such as water can be rapidly brought into affinity with the surface of the layer A. This can help to lower the water peeling force (N2). The amount of the carboxy group-containing monomer to be used may be, for example, 0.05% by weight or more, 0.1% by weight or more, 0.3% by weight or more, 0.5% by weight or more, or 0.8% by weight or more of the total monomer component. Further, the proportion of the carboxy group-containing monomer may be, for example, 15% by weight or less, 10% by weight or less, 5% by weight or less, 4.5% by weight or less, 3.5% by weight or less, or 3.0% by weight. % Or less may be sufficient, and 2.5 weight% or less may be sufficient. The fact that the amount of the carboxyl group-containing monomer is not too large is preferable from the viewpoint of suppressing the diffusion of water into the bulk of the layer A and suppressing a decrease in the water-resistant adhesion (N1). In addition, the fact that the amount of the carboxy group-containing monomer is not too large can be advantageous also from the viewpoint of preventing the water used for the measurement of the water peeling force (N2) from being absorbed by the layer A, and preventing water shortage during peeling.

In some embodiments, the monomer component may contain a hydroxyl group-containing monomer. By use of a hydroxyl-containing monomer, the cohesive strength and crosslinking density of the pressure-sensitive adhesive can be adjusted, and the state adhesion (N0) can be improved. In the case of using a hydroxyl-containing monomer, the amount used is not particularly limited, and for example, it may be 0.01% by weight or more, 0.1% by weight or more, or 0.5% by weight or more of the total monomer component. In addition, from the viewpoint of suppressing excessive water diffusion into the bulk of the layer A, in some embodiments, the amount of the hydroxyl group-containing monomer to be used is suitably 40% by weight or less, for example, of the entire monomer component, and 30% by weight. It may be set as% or less, may be set as 20 wt% or less, and may be set as 10 wt% or less, 5 wt% or less, or 3 wt% or less. The pressure-sensitive adhesive sheet disclosed herein can be preferably implemented even in an embodiment in which a hydroxyl-containing monomer is not substantially used as the monomer component of the layer A.

In some embodiments, the monomer component may contain an alkoxysilyl group-containing monomer. The alkoxysilyl group-containing monomer is typically an ethylenically unsaturated monomer having at least one (preferably two or more, for example, two or three) alkoxysilyl groups in one molecule, and specific examples thereof are described above. As described. The alkoxysilyl group-containing monomer may be used alone or in combination of two or more. By use of an alkoxysilyl group-containing monomer, a crosslinked structure by condensation reaction (silanol condensation) of silanol groups can be introduced into the pressure-sensitive adhesive layer. In addition, the alkoxysilyl group-containing monomer can also be grasped as a silane coupling agent described later.

In the aspect in which the monomer component contains an alkoxysilyl group-containing monomer, the ratio of the alkoxysilyl group-containing monomer to the entire monomer component can be, for example, 0.005% by weight or more, and usually 0.01% by weight or more. It is appropriate. In addition, the ratio of the alkoxysilyl group-containing monomer may be, for example, 0.5% by weight or less, 0.1% by weight or less, or 0.05% by weight or less from the viewpoint of improving the adhesion to the adherend.

The composition of the monomer component is such that the glass transition temperature (hereinafter also referred to as "glass transition temperature of an acrylic polymer") determined by Fox's formula based on the composition of the monomer component is -75°C or more and -10°C or less. Can be set. In some embodiments, the glass transition temperature (Tg) of the acrylic polymer is suitably -20°C or less, preferably -30°C or less, more preferably -40°C or less, and furthermore -50°C or less. It is preferable and, for example, -55 degreeC or less may be sufficient. When the Tg of the acrylic polymer is lowered, the adhesion of the layer A to the adherend generally tends to be improved. According to the layer A having high adhesion to the adherend, it is easy to suppress water intrusion into the interface between the adherend and the layer A in a phase where peeling of the pressure-sensitive adhesive sheet is not intended. This can be advantageous from the viewpoint of improving the water-resistant adhesive force N1 and reducing the rate of decrease in the water-resistant adhesive force. In addition, the Tg of the acrylic polymer may be, for example, -70°C or higher, or -65°C or higher, from the viewpoint of making it easy to increase the state adhesive force (N0).

Here, the formula of Fox is a relational expression between the Tg of the copolymer and the glass transition temperature Tgi of the homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer, as shown below.

1/Tg = Σ(Wi/Tgi)

In addition, in the formula of Fox, Tg is the glass transition temperature (unit: K) of the copolymer, Wi is the weight fraction of the monomer i in the copolymer (the copolymerization ratio based on weight), and Tgi is the homogeneity of the monomer i. It shows the glass transition temperature (unit: K) of a polymer.

As the glass transition temperature of the homopolymer used for calculating Tg, the value described in publicly known data is assumed to be used. For example, for the following monomers, the following values are used as the glass transition temperature of the homopolymer of the monomer.

2-ethylhexyl acrylate -70°C

n-butyl acrylate -55 ℃

Methyl methacrylate 105 ℃

Methyl acrylate 8 ℃

Acrylic acid 106 ℃

Methacrylic acid 228 ℃

For the glass transition temperature of a homopolymer of a monomer other than those exemplified above, the numerical values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) shall be used. When plural types of values are described in this document, the highest value is adopted.

For monomers for which the homopolymer glass transition temperature is not described in the Polymer Handbook as well, a value obtained by the following measurement method is used (see Japanese Patent Application Laid-Open No. 2007-51271). Specifically, 100 parts by weight of a monomer, 0.2 parts by weight of azobisisobutyronitrile, and 200 parts by weight of ethyl acetate as a polymerization solvent were added to a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube, and a reflux cooling tube, and nitrogen gas was added. Stir for 1 hour while flowing. After removing oxygen in the polymerization system in this manner, the temperature is raised to 63°C and reacted for 10 hours. Then, it is cooled to room temperature, and a homopolymer solution having a solid content concentration of 33% by weight is obtained. Next, this homopolymer solution is cast and dried on a release liner to prepare a test sample (sheet-shaped homopolymer) having a thickness of about 2 mm. This test sample was punched into a disk shape with a diameter of 7.9 mm, sandwiched between parallel plates, and sheared at a frequency of 1 Hz using a viscoelastic tester (ARES, manufactured by Rheometrics), and temperature range The viscoelasticity is measured by shear mode at a temperature rising rate of -70 to 150°C and 5°C/min, and the peak top temperature of tan δ is taken as Tg of the homopolymer.

The pressure-sensitive adhesive layer disclosed herein uses a pressure-sensitive adhesive composition comprising a monomer component of the composition as described above in the form of a polymerized product, an unpolymerized product (i.e., a form in which the polymerizable functional group is unreacted), or a mixture thereof. Can be formed. The pressure-sensitive adhesive composition is a water-dispersible pressure-sensitive adhesive composition in which a pressure-sensitive adhesive (adhesive component) is dispersed in water, a solvent-type pressure-sensitive adhesive composition containing a pressure-sensitive adhesive in an organic solvent, and cured by active energy rays such as ultraviolet rays or radiation to cure the pressure-sensitive adhesive. It may be in various forms, such as an active energy ray-curable pressure-sensitive adhesive composition prepared to form, and a hot-melt-type pressure-sensitive adhesive composition that is coated in a hot-melt state and cooled to near room temperature to form a pressure-sensitive adhesive.

In polymerization, a known or commonly used thermal polymerization initiator or photopolymerization initiator can be used depending on the polymerization method or polymerization mode. Such a polymerization initiator can be used individually by 1 type or by combining 2 or more types suitably.

The thermal polymerization initiator is not particularly limited, and for example, an azo polymerization initiator, a peroxide initiator, a redox initiator obtained by a combination of a peroxide and a reducing agent, a substituted ethane initiator, and the like can be used. More specifically, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(2-amidino Propane)dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(N,N'- Azo initiators such as dimethylene isobutylamidine) and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate; Persulfates, such as potassium persulfate and ammonium persulfate, for example; Peroxide initiators such as benzoyl peroxide, t-butyl hydroperoxide, and hydrogen peroxide; Substituted ethane initiators such as phenyl substituted ethane; For example, redox initiators such as a combination of persulfate and sodium hydrogen sulfite, and a combination of peroxide and sodium ascorbate; Etc. are illustrated, but are not limited to these. In addition, thermal polymerization can be preferably carried out at a temperature of, for example, about 20 to 100°C (typically 40 to 80°C).

Although it does not specifically limit as a photoinitiator, For example, a ketal-type photoinitiator, acetophenone-type photoinitiator, a benzoin ether-type photoinitiator, an acylphosphine oxide-type photoinitiator, α-ketol-type photoinitiator A polymerization initiator, an aromatic sulfonyl chloride photoinitiator, a photoactive oxime photoinitiator, a benzoin photoinitiator, a benzyl photoinitiator, a benzophenone photoinitiator, a thioxanthone photoinitiator, etc. can be used. have.

The amount of such thermal polymerization initiator or photopolymerization initiator used may be a conventional amount depending on the polymerization method or polymerization mode, and is not particularly limited. For example, about 0.001 to 5 parts by weight of a polymerization initiator (typically about 0.01 to 2 parts by weight, for example, about 0.01 to 1 part by weight) can be used based on 100 parts by weight of the monomer to be polymerized.

For the polymerization, if necessary, various conventionally known chain transfer agents (which can also be regarded as molecular weight modifiers or polymerization degree modifiers) can be used. Mercaptans, such as n-dodecyl mercaptan, t-dodecyl mercaptan, and thioglycolic acid, can be used as a chain transfer agent. Alternatively, a chain transfer agent that does not contain a sulfur atom (non-sulfur chain transfer agent) may be used. Specific examples of the non-sulfur chain transfer agent include anilines such as N,N-dimethylaniline and N,N-diethylaniline; Terpenoids, such as α-pinene and terpinolene; Styrene, such as α-methylstyrene and α-methylstyrene dimer; Compounds having a benzylidene group such as dibenzylidene acetone, cinnamyl alcohol and cinnamylaldehyde; Hydroquinones such as hydroquinone and naphthohydroquinone; Quinones, such as benzoquinone and naphthoquinone; Olefins such as 2,3-dimethyl-2-butene and 1,5-cyclooctadiene; Alcohols such as phenol, benzyl alcohol, and allyl alcohol; Benzyl hydrogens such as diphenylbenzene and triphenylbenzene; And the like.

A chain transfer agent can be used individually by 1 type or in combination of 2 or more types. When a chain transfer agent is used, the amount thereof can be, for example, about 0.01 to 1 part by weight based on 100 parts by weight of the monomer component. The technique disclosed herein can be preferably implemented even in an embodiment in which a chain transfer agent is not used.

The molecular weight of the polymer obtained by appropriately employing the various polymerization methods described above is not particularly limited, and may be set in an appropriate range according to the required performance. The weight average molecular weight (Mw) of the polymer is usually approximately 10 × 10 ⁴ or more (for example, 20 × 10 ⁴ or more), and from the viewpoint of balancing cohesive strength and adhesive force in a balanced manner, it is more than 30 × 10 ⁴ It is suitable. From the viewpoint of obtaining good adhesion reliability even in a high-temperature environment, the polymer according to one aspect is preferably 40 × 10 ⁴ or more (typically about 50 × 10 ⁴ or more, for example, about 55 × 10 ⁴ or more) of Mw Has. The upper limit of the Mw of the polymer may be usually about 500 × 10 ⁴ or less (eg, about 150 × 10 ⁴ or less). The Mw may be approximately 75×10 ⁴ or less. Here, Mw means a value in terms of standard polystyrene obtained by gel permeation chromatography (GPC). As the GPC device, the model name "HLC-8320GPC" (column: TSKgelGMH(S), manufactured by Tosoh Corporation) may be used, for example. The same is true for the examples described later. The Mw may be Mw of the polymer in any of the pressure-sensitive adhesive layers in the pressure-sensitive adhesive composition.

The pressure-sensitive adhesive sheet according to several preferred embodiments has a layer A formed from a water-dispersible pressure-sensitive adhesive composition. As a representative example of the water-dispersible adhesive composition, an emulsion-type adhesive composition is mentioned. The emulsion-type pressure-sensitive adhesive composition typically contains a polymerized product of a monomer component and an additive used as necessary.

The emulsion polymerization of the monomer component is usually carried out in the presence of an emulsifier. The emulsifier for emulsion polymerization is not particularly limited, and known anionic emulsifiers, nonionic emulsifiers, and the like can be used. Emulsifiers can be used alone or in combination of two or more.

Non-limiting examples of anionic emulsifiers include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene lauryl sulfate, sodium polyoxyethylene alkyl ether sulfate, polyoxyethylene alkylphenyl ether ammonium sulfate, polyoxy Sodium ethylene alkyl phenyl ether sulfate, sodium polyoxyethylene alkyl sulfosuccinate, etc. are mentioned. Non-limiting examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene polyoxypropylene block polymer. You may use an emulsifier (reactive emulsifier) having a reactive functional group. Examples of the reactive emulsifier include a radically polymerizable emulsifier having a structure in which a radical polymerizable functional group such as a propenyl group or an allyl ether group is introduced into the anionic emulsifier or nonionic emulsifier described above.

The amount of emulsifier used in emulsion polymerization may be, for example, 0.2 parts by weight or more, 0.5 parts by weight or more, 1.0 parts by weight or more, or 1.5 parts by weight or more, based on 100 parts by weight of the monomer component. In addition, from the viewpoint of improving the water-resistant adhesive strength (N1), reducing the water-resistant adhesive strength, or improving the transparency of the pressure-sensitive adhesive layer, in some embodiments, the amount of the emulsifier used is usually 10 parts by weight based on 100 parts by weight of the monomer component. It is appropriate to be below, preferably 5 parts by weight or less, and may be 3 parts by weight or less. In addition, the emulsifier used for emulsion polymerization here can also function as a water affinity agent for layer A.

According to emulsion polymerization, a polymerization reaction solution in the form of an emulsion in which a polymer of a monomer component is dispersed in water is obtained. The water-dispersible pressure-sensitive adhesive composition used for forming the layer A can be preferably prepared using the polymerization reaction solution.

The pressure-sensitive adhesive sheet according to several other preferred embodiments may have a layer A formed from a solvent-type pressure-sensitive adhesive composition. The solvent-type pressure-sensitive adhesive composition typically contains a solution polymerized product of a monomer component and an additive used as necessary. The solvent (polymerization solvent) used for solution polymerization can be appropriately selected from known organic solvents. For example, aromatic compounds such as toluene (typically aromatic hydrocarbons); Esters such as ethyl acetate and butyl acetate; Aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane; Halogenated alkanes such as 1,2-dichloroethane; Lower alcohols such as isopropyl alcohol (for example, monohydric alcohols having 1 to 4 carbon atoms); ethers such as tert-butyl methyl ether; Ketones such as methyl ethyl ketone; Any one type of solvent selected from, for example, or a mixed solvent of two or more types can be used. By solution polymerization, a polymerization reaction solution in a form in which a polymer of a monomer component is dissolved in a polymerization solvent is obtained. The solvent-type pressure-sensitive adhesive composition used to form the layer A can be preferably prepared using the polymerization reaction solution.

The pressure-sensitive adhesive sheet according to several other preferred embodiments may have a layer A formed from an active energy ray-curable pressure-sensitive adhesive composition. Here, in the present specification, the "active energy ray" refers to an energy ray having energy capable of causing a chemical reaction such as a polymerization reaction, a crosslinking reaction, and decomposition of an initiator. Examples of the active energy rays here include light such as ultraviolet rays, visible rays, and infrared rays, radiation such as α rays, β rays, γ rays, electron rays, neutron rays, and X rays. As one suitable example of an active energy ray-curable adhesive composition, a photocurable adhesive composition is mentioned. The photo-curable pressure-sensitive adhesive composition has an advantage that it can be easily formed even if it is a thick pressure-sensitive adhesive layer. Among them, an ultraviolet curable pressure-sensitive adhesive composition is preferred.

The photocurable pressure-sensitive adhesive composition typically contains at least a part of the monomer component of the composition (a part of the type of the monomer or a part of the amount) in the form of a polymer. The polymerization method for forming the polymer is not particularly limited, and various conventionally known polymerization methods can be appropriately employed. For example, thermal polymerization such as solution polymerization, emulsion polymerization, and bulk polymerization (typically, it is carried out in the presence of a thermal polymerization initiator); Photopolymerization performed by irradiating light such as ultraviolet rays (typically, it is performed in the presence of a photopolymerization initiator); radiation polymerization performed by irradiating radiation such as β-ray and γ-ray; Etc. can be appropriately adopted. Among them, photopolymerization is preferred.

The photocurable pressure-sensitive adhesive composition according to a preferred aspect contains a partially polymerized product of a monomer component. Such a partial polymer is typically a mixture of a polymer derived from a monomer component and an unreacted monomer, and preferably exhibits a syrup form (a viscous liquid). Hereinafter, a partial polymer of such a property may be referred to as "monomer syrup" or simply "syrup". The polymerization method when partially polymerizing the monomer component is not particularly limited, and various polymerization methods as described above can be appropriately selected and used. From the viewpoint of efficiency and simplicity, a photopolymerization method can be preferably employed. According to photopolymerization, the polymerization conversion rate (monomer conversion) of a monomer component can be easily controlled by polymerization conditions such as an irradiation amount of light (amount of light).

The polymerization conversion ratio of the monomer mixture in the partial polymerized product is not particularly limited. The polymerization conversion ratio can be, for example, approximately 70% by weight or less, and is preferably approximately 60% by weight or less. From the viewpoint of ease of preparation and coatability of the pressure-sensitive adhesive composition containing the partially polymerized product, usually, the polymerization conversion ratio is preferably approximately 50% by weight or less, and approximately 40% by weight or less (for example, approximately 35% by weight or less). Is preferred. The lower limit of the polymerization conversion rate is not particularly limited, but is typically approximately 1% by weight or more, and usually approximately 5% by weight or more is suitable.

In the pressure-sensitive adhesive composition containing the partial polymerized product of the monomer component, for example, a monomer mixture containing the total amount of the monomer component used in the preparation of the pressure-sensitive adhesive composition is partially polymerized by an appropriate polymerization method (for example, photopolymerization). It can be obtained by doing. In addition, the pressure-sensitive adhesive composition containing a partial polymerization product of the monomer component may be a mixture of a partial polymerization product or a complete polymerization product of a monomer mixture containing a part of the monomer components used in the preparation of the pressure-sensitive adhesive composition, and the remaining monomer component or a partial polymerization product thereof. do. In addition, in this specification, a "completely polymerized product" means that the polymerization conversion ratio is more than 95 weight%.

In the pressure-sensitive adhesive composition containing the partial polymer, other components (eg, photopolymerization initiators, polyfunctional monomers, crosslinking agents, water affinity agents, etc.) may be blended as needed. The method of blending such other components is not particularly limited, and for example, may be contained in advance in the monomer mixture or may be added to the partial polymerized product.

(Water affinity)

In the PSA sheet disclosed herein, it is preferable that the layer A constituting one surface of the PSA layer contains a water affinity agent in addition to the polymerization reaction product of the monomer component. For example, a pressure-sensitive adhesive sheet comprising an acrylic polymer as the polymerization product and further comprising an A layer containing a water affinity agent is preferable.

As the water affinity agent, various materials capable of exerting an action of increasing the water affinity of the surface of the layer A by being contained in the layer A can be appropriately selected and used. By increasing the water affinity of the A layer, an aqueous liquid such as water can be more quickly made affinity to the surface of the A layer. Thereby, for example, in the measurement of the water peeling force (N2), the first drop of water dripped can be spread evenly on the surface of the layer A by following the movement of the peeling wire of the adhesive sheet from the adherend. There is, and water peeling force (N2) can be effectively reduced. By the same action, in the adhesive sheet peeling method comprising moving the peeling wire while introducing an aqueous liquid such as water into the interface between the adhesive sheet and the adherend, the peelability of the adhesive sheet from the adherend can be improved. .

As the water affinity agent, known surfactants (anionic surfactants, nonionic surfactants, cationic surfactants, etc.), hydrophilic plasticizers (water-soluble plasticizers may be used), water-soluble polymers, and the like can be used. As the surfactant, a nonionic surfactant, an anionic surfactant, and combinations thereof are preferable. Water affinity agents may be used alone or in combination of two or more.

Various polyols (preferably polyether polyols) can be used as the hydrophilic plasticizer. Specific examples of the polyol include polyethylene glycol, polypropylene glycol, polyoxypropylene sorbitol ether, and polyglycerin. These hydrophilic plasticizers can be used alone or in combination of two or more.

As a water-soluble polymer, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, etc. are mentioned, for example.

In some embodiments, as the hydrophilic plasticizer, a compound having a polyoxyalkylene skeleton can be preferably employed. Examples of the compound having a polyoxyalkylene skeleton include polyalkylene glycols such as polyethylene glycol (PEG) and polypropylene glycol (PPG); Polyether containing polyoxyethylene units, polyether containing polyoxypropylene units (e.g., polyoxypropylene sorbitol ether), compounds containing oxyethylene units and oxypropylene units (the arrangement of these units is random It may be or may be a block shape.); Derivatives thereof; Etc. can be used. Moreover, among the surfactants mentioned above, a compound having a polyoxyalkylene skeleton can also be used. These can be used alone or in combination of two or more. Among them, it is preferable to use a compound containing a polyoxyethylene skeleton (also referred to as a polyoxyethylene segment), and PEG is more preferable.

The molecular weight (chemical formula) of the compound (e.g., PEG) having a polyoxyalkylene skeleton is not particularly limited, and is suitable, for example, less than 1000, and from the viewpoint of the pressure-sensitive adhesive composition formulation, approximately 600 or less (e.g. 500 It is preferable that it is below). The lower limit of the molecular weight of the compound having a polyoxyalkylene skeleton (eg, polyethylene glycol) is not particularly limited, and those having a molecular weight of about 100 or more (eg about 200 or more, and further about 300 or more) are preferably used. .

Examples of the anionic surfactant include alkylbenzene sulfonates such as nonylbenzenesulfonate and dodecylbenzenesulfonate (for example, sodium dodecylbenzenesulfonate); Alkyl sulfates such as lauryl sulfate (for example, sodium lauryl sulfate, ammonium lauryl sulfate) and octadecyl sulfate; Fatty acid salt; Polyoxyethylene alkyl ether sulfates such as polyoxyethylene octadecyl ether sulfate and polyoxyethylene lauryl ether sulfate (for example, sodium polyoxyethylene alkyl ether sulfate), polyoxyethylene alkyl such as polyoxyethylene lauryl phenyl ether sulfate Polyether sulfates, such as a phenyl ether sulfate (for example, polyoxyethylene alkylphenyl ether ammonium sulfate, polyoxyethylene alkylphenyl ether sodium sulfate, etc.), and polyoxyethylene styrenated phenyl ether sulfate; Polyoxyethylene alkyl ether phosphate such as polyoxyethylene stearyl ether phosphate and polyoxyethylene lauryl ether phosphate; Polyoxyethylene alkyl ether phosphate salts such as sodium salt and potassium salt of the polyoxyethylene alkyl ether phosphate; Sulfosuccinates such as lauryl sulfosuccinate and polyoxyethylene lauryl sulfosuccinate (for example, sodium polyoxyethylene alkyl sulfosuccinate); Polyoxyethylene alkyl ether acetate; And the like. When the anionic surfactant forms a salt, the salt may be, for example, a metal salt such as sodium salt, potassium salt, calcium salt, magnesium salt (preferably monovalent metal salt), ammonium salt, amine salt, etc. have. Anionic surfactants can be used alone or in combination of two or more.

Examples of cationic surfactants include polyetheramines such as polyoxyethylene laurylamine and polyoxyethylene stearylamine.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether (polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, etc.); Polyoxyethylene alkylphenyl ether (polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, etc.); Sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, and sorbitan monooleate; Polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan triisostearate, polyoxyethylene sorb Polyoxyethylene sorbitan fatty acid esters such as non-monooleate and polyoxyethylene sorbitan trioleate; Polyoxyalkylene ethers such as polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, and polyoxyethylene bisphenol A ether; Polyoxyethylene fatty acid ester; Polyoxyethylene glyceryl ether fatty acid ester; And polyoxyethylene/polyoxypropylene block polymers. Nonionic surfactants can be used alone or in combination of two or more.

In some embodiments, for example, an anionic surfactant having at least one of a -POH group, a -COH group and a -SOH group can be preferably used. Among them, a surfactant having a -POH group is preferable. Such a surfactant typically contains a phosphoric acid ester structure, and, for example, a monoester of phosphoric acid (ROP(=O)(OH) ₂ ; where R is a monovalent organic group), a diester ((RO) ₂ P(=O)OH; wherein R may be a mixture containing both monoesters and diesters), the same or different monovalent organic groups. As a preferred example of the surfactant having a -POH group, polyoxyethylene alkyl ether phosphoric acid ester is mentioned. The number of carbon atoms of the alkyl group in the polyoxyethylene alkyl ether phosphate may be, for example, 6 to 20, 8 to 20, 10 to 20, 12 to 20, or 14 to 20.

The HLB of a water affinity agent is not specifically limited, For example, it is 3 or more, approximately 6 or more is suitable, and may be 8 or more (for example, 9 or more). In one preferred embodiment, the HLB of the water affinity agent is 10 or more. Thereby, the water peelability tends to be expressed preferably. The HLB is more preferably 11 or more, still more preferably 12 or more, and particularly preferably 13 or more (eg 14 or more). By including a water affinity agent (typically a surfactant) having HLB in the above range in the layer A, water releasability can be more effectively expressed. The upper limit of the HLB is 20 or less, for example, 18 or less, 16 or less, and 15 or less.

In addition, HLB in this specification is the Hydrophile-Lipophile Balance by Griffin, is a value indicating the degree of affinity of a surfactant to water or oil, and the ratio of hydrophilicity and lipophilicity is expressed as a value between 0 and 20. will be. The definition of HLB is W. C. Griffin: J. Soc. Cosmetic Chemists, 1,311 (1949) Ina, Koshitami Takahashi, Yoshirou Namba, Motoo Koike, Masao Kobayashi, ``Surface Activator Handbook,'' 3rd edition, published by Kogaku Book Company, November 25, 1978, p179 It is as described in -182 and the like. The water affinity agent having the HLB can be selected based on the technical common knowledge of a person skilled in the art, taking the above reference into consideration as necessary.

It is preferable that such a water affinity agent is contained in the A layer in the form of a glass. As the water affinity agent, a liquid at room temperature (about 25°C) is preferably used from the viewpoint of the preparation of the pressure-sensitive adhesive composition. In addition, among the surfactants, a compound having a polyoxyalkylene skeleton is present, and it is needless to say that the opposite is also true.

The A layer comprising a water affinity agent is typically formed from a pressure-sensitive adhesive composition comprising a water affinity agent. The pressure-sensitive adhesive composition may be any of the aforementioned water-dispersible pressure-sensitive adhesive composition, solvent-type pressure-sensitive adhesive composition, active energy ray-curable pressure-sensitive adhesive composition, and hot-melt pressure-sensitive adhesive composition. In some embodiments, the layer A containing a water affinity agent may be an adhesive layer formed from a photo-curable or solvent-type adhesive composition. A layer may have photocrosslinking property.

The content of the water affinity agent in the layer A is not particularly limited, and can be set so that the effect of using the water affinity agent is appropriately exhibited. In some embodiments, the content of the water affinity agent may be, for example, 0.001 parts by weight or more per 100 parts by weight of the monomer component constituting the polymer (eg, acrylic polymer) contained in the layer A. It is appropriate to use 0.01 parts by weight or more, 0.03 parts by weight or more, 0.07 parts by weight or more, or 0.1 parts by weight or more. In some preferred embodiments, the content of the water affinity agent may be, for example, 0.2 parts by weight or more based on 100 parts by weight of the monomer component, 0.5 parts by weight or more, or 1.0 parts by weight from the viewpoint of obtaining a higher effect. It may be more than or equal to 1.5 parts by weight or more. In addition, from the viewpoint of suppressing excessive water diffusion to the bulk of the layer A, in some embodiments, the amount of water affinity agent used may be, for example, 20 parts by weight or less based on 100 parts by weight of the monomer component. It is appropriate to use 10 parts by weight or less of silver, preferably 5 parts by weight or less, and may be 3 parts by weight or less. The fact that the content of the water-affinity agent is not too large is also preferable from the viewpoint of improving the water-resistant adhesive force (N1), reducing the rate of decrease in the water-resistant adhesive force, or improving the transparency of the adhesive layer. For example, in some embodiments, the content of the water affinity agent to 100 parts by weight of the monomer component may be less than 2 parts by weight, less than 1 part by weight, less than 0.7 parts by weight, and less than 0.3 parts by weight. It may be, and it may be less than 0.2 parts by weight. A water affinity agent having an HLB of 10 or more tends to exhibit good water peelability even when used in a small amount.

(Silane coupling agent)

In some embodiments, layer A may contain a silane coupling agent. According to the layer A containing the silane coupling agent, a pressure-sensitive adhesive sheet having a low water-resistance adhesion reduction rate and a high water peel adhesion reduction rate (and/or a long water entry distance) can be preferably realized.

As the silane coupling agent, it has an epoxy structure such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Silicon compound; Amino group-containing silicon compounds such as 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropyltrimethoxysilane, and N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane; 3-chloropropyltrimethoxysilane; Trimethoxysilane containing acetoacetyl group; (Meth)acrylic group-containing silane coupling agents such as 3-acryloxypropyl trimethoxysilane and 3-methacryloxypropyl triethoxysilane; An isocyanate group-containing silane coupling agent, such as 3-isocyanate propyl triethoxysilane, etc. are mentioned. In some aspects, by employing a silane coupling agent having a trialkoxysilyl group, the above-described effect can be more preferably exhibited. Among them, as preferable silane coupling agents, 3-glycidoxypropyltrimethoxysilane and acetoacetyl group-containing trimethoxysilane are exemplified.

The amount of the silane coupling agent used can be set so as to obtain a desired effect of use, and is not particularly limited. In some embodiments, the amount of the silane coupling agent used may be, for example, 0.001 parts by weight or more, based on 100 parts by weight of the monomer component constituting the polymer contained in the layer A, and 0.005 parts by weight from the viewpoint of obtaining a higher effect. It may be at least part, 0.01 part by weight or more, and may be at least 0.015 part by weight. In addition, from the viewpoint of improving the adhesion to the adherend, in some aspects, the amount of the silane coupling agent used may be, for example, 3 parts by weight or less, based on 100 parts by weight of the monomer component constituting the layer A, 1 It may be less than or equal to 0.5 parts by weight.

In some aspects, the A layer may contain a silane coupling agent in the form of glass. The A layer in such an aspect may be, for example, an adhesive layer formed from a photo-curable or solvent-type adhesive composition. A layer may have photocrosslinking property.

In addition, in an aspect in which the monomer component contains an alkoxysilyl group-containing monomer, the alkoxysilyl group-containing monomer may be used as a part or all of the silane coupling agent contained in the layer A. The A layer in such an aspect may be, for example, an adhesive layer formed from a water-dispersible adhesive composition.

(Crosslinking agent)

In the A layer, a crosslinking agent can be contained as needed. The kind of crosslinking agent is not particularly limited, and for example, a crosslinking agent appropriately selected from conventionally known crosslinking agents can be used. Specific examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, a carbodiimide crosslinking agent, a melamine crosslinking agent, a urea crosslinking agent, a metal alkoxide crosslinking agent, a metal chelate crosslinking agent, a metal salt system. A crosslinking agent, a hydrazine type crosslinking agent, an amine type crosslinking agent, etc. are mentioned. These can be used alone or in combination of two or more.

As an example of the isocyanate-based crosslinking agent, a polyfunctional isocyanate compound having a bifunctional or higher function can be used. For example, aromatic isocyanates such as tolylene diisocyanate, xylene diisocyanate, polymethylene polyphenyl diisocyanate, tris(p-isocyanatophenyl)thiophosphate, and diphenylmethane diisocyanate; Alicyclic isocyanates such as isophorone diisocyanate; Aliphatic isocyanates such as hexamethylene diisocyanate; And the like. Commercially available products include trimethylolpropane/tolylenediisocyanate trimer adduct (manufactured by Tosoh Corporation, brand name ``Colonate L''), trimethylolpropane/hexamethylenediisocyanate terpolymer adduct (manufactured by Tosoh Corporation, brand name ``Colonate HL''). ”) and isocyanate adducts such as an isocyanurate product of hexamethylene diisocyanate (manufactured by Tosoh Corporation, brand name “Colonate HX”), etc. can be illustrated. In the water-dispersible pressure-sensitive adhesive composition, use of an isocyanate-based crosslinking agent capable of dissolving or dispersing in water is preferred. For example, a water-soluble, water-dispersible, or self-emulsifying type isocyanate crosslinking agent can be preferably employed. An isocyanate-based crosslinking agent of a so-called blocked isocyanate type in which an isocyanate group is blocked can be preferably used.

As the epoxy-based crosslinking agent, one having two or more epoxy groups in one molecule can be used without particular limitation. An epoxy-based crosslinking agent having 3 to 5 epoxy groups per molecule is preferred. Specific examples of the epoxy crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, etc. are mentioned. Commercially available products of the epoxy-based crosslinking agent include the brand names ``TETRAD-X'' and ``TETRAD-C'' manufactured by Mitsubishi Gas Chemicals, the brand name ``Epiclon CR-5L'' manufactured by DIC, and the brand name ``Denacol EX'' manufactured by Nagase Chemtex. -512", a brand name "TEPIC-G" manufactured by Nissan Chemical Industries, etc. are mentioned. In the water-dispersible pressure-sensitive adhesive composition, it is preferable to use an epoxy-based crosslinking agent that can be dissolved or dispersed in water.

As the oxazoline crosslinking agent, one having one or more oxazoline groups in one molecule can be used without particular limitation. In the water-dispersible pressure-sensitive adhesive composition, use of an oxazoline-based crosslinking agent capable of dissolving or dispersing in water is preferred.

Examples of the aziridine crosslinking agent include trimethylolpropanetris [3-(1-aziridinyl)propionate], trimethylolpropanetris [3-(1-(2-methyl)aziridinylpropionate)], etc. Can be mentioned.

As the carbodiimide crosslinking agent, a low-molecular compound or a high-molecular compound having two or more carbodiimide groups can be used. In the water-dispersible pressure-sensitive adhesive composition, it is preferable to use a carbodiimide crosslinking agent that can be dissolved or dispersed in water.

In some embodiments, peroxide may be used as the crosslinking agent. As the peroxide, di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate, t- Hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxyisobutylate, dibenzoyl peroxide And the like. Among these, as peroxides having particularly excellent crosslinking reaction efficiency, di(4-t-butylcyclohexyl)peroxydicarbonate, dilauroyl peroxide, dibenzoyl peroxide, and the like can be mentioned. In addition, when a peroxide is used as the polymerization initiator, the peroxide remaining without being used in the polymerization reaction may be used for the crosslinking reaction. In that case, the residual amount of peroxide is quantified, and when the proportion of peroxide is less than the predetermined amount, peroxide may be added to a predetermined amount as necessary. The peroxide can be quantified by the method described in Japanese Patent Publication No. 4971517.

The content of the crosslinking agent (when two or more types of crosslinking agents are included, their total amount) is not particularly limited. From the viewpoint of realizing a pressure-sensitive adhesive that exhibits adhesive properties such as adhesion and cohesiveness in a balanced manner, it is appropriate that the content of the crosslinking agent is usually approximately 5 parts by weight or less based on 100 parts by weight of the monomer component used in the preparation of the pressure-sensitive adhesive composition. And, it is preferable to set it as about 0.001 to 5 parts by weight, more preferably to set it as about 0.001 to 4 parts by weight, and still more preferably to set it as about 0.001 to 3 parts by weight. Alternatively, it may be a pressure-sensitive adhesive composition not containing a crosslinking agent as described above. For example, when a photocurable pressure-sensitive adhesive composition is used as the pressure-sensitive adhesive composition disclosed herein, the pressure-sensitive adhesive composition may be one that does not substantially contain a crosslinking agent such as an isocyanate-based crosslinking agent. Here, that the pressure-sensitive adhesive composition substantially does not contain a crosslinking agent (typically an isocyanate-based crosslinking agent) means that the amount of the crosslinking agent per 100 parts by weight of the monomer component is less than 0.05 parts by weight (for example, less than 0.01 parts by weight). And the amount of the crosslinking agent based on 100 parts by weight of the monomer component is 0 parts by weight.

In order to advance the crosslinking reaction more effectively, you may use a crosslinking catalyst. Examples of the crosslinking catalyst include metal-based crosslinking catalysts such as tetra-n-butyl titanate, tetraisopropyl titanate, ferric nasemite, butyl tin oxide, and dioctyl tin dilaurate. Among them, tin-based crosslinking catalysts such as dioctyl tin dilaurate are preferable. The amount of crosslinking catalyst used is not particularly limited. The amount of the crosslinking catalyst used for 100 parts by weight of the monomer component used in the preparation of the pressure-sensitive adhesive composition may be, for example, approximately 0.0001 parts by weight or more and 1 part by weight or less, 0.001 parts by weight or more and 0.1 parts by weight or less, and 0.005 parts by weight or more. 0.5 parts by weight or less may be sufficient.

In the pressure-sensitive adhesive composition used for formation of the layer A, as a crosslinking retardant, a compound that generates keto-enol tautomerism can be contained. For example, in a pressure-sensitive adhesive composition containing an isocyanate-based crosslinking agent or a pressure-sensitive adhesive composition that can be used by blending an isocyanate-based crosslinking agent, an aspect including a compound generating keto-enol tautomerism can be preferably employed. Thereby, the effect of extending the pot life of the pressure-sensitive adhesive composition can be realized.

As the compound generating keto-enol tautomerism, various β-dicarbonyl compounds can be used. As a specific example, β-diketones, such as acetylacetone and 2,4-hexanedione; Acetoacetate esters such as methyl acetoacetate and ethyl acetoacetate; Propionyl acetate esters such as propionyl ethyl acetate; Isobutyryl acetate, such as isobutyryl ethyl acetate; Malonic acid esters such as methyl malonate and ethyl malonate; And the like. Among them, preferred compounds include acetylacetone and acetoacetic acid ester. The compounds that generate keto-enol tautomerism can be used alone or in combination of two or more.

The content of the compound generating keto-enol tautomerism may be, for example, 0.1 parts by weight or more and 20 parts by weight or less, and usually 0.5 parts by weight or more and 15 parts by weight, based on 100 parts by weight of the monomer component used in the preparation of the pressure-sensitive adhesive composition. It is appropriate to use parts by weight or less, for example, 1 part by weight or more and 10 parts by weight or less, and it may be 1 part by weight or more and 5 parts by weight or less.

(Polyfunctional monomer)

In the A layer, a polyfunctional monomer may be used if necessary. The polyfunctional monomer may be useful for purposes such as adjustment of cohesive force by being used in place of the crosslinking agent as described above or in combination with the crosslinking agent. For example, in the pressure-sensitive adhesive layer formed from a photo-curable pressure-sensitive adhesive composition, a polyfunctional monomer can be preferably used. In the pressure-sensitive adhesive sheet before being affixed to the adherend, the polyfunctional monomer contained in the pressure-sensitive adhesive layer may be a form in which the polymerizable functional group is unreacted, may be partially reacted, or may be a form after reaction.

As a polyfunctional monomer, for example, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol Di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene glycol di(meth)acrylate, 1,6 -Hexanedioldi(meth)acrylate, 1,12-dodecanedioldi(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl(meth)acrylate , Vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyldiol (meth)acrylate, hexyldiol di (meth)acrylate, and the like. Among them, trimethylolpropane tri(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, and dipentaerythritol hexa(meth)acrylate can be preferably used. The polyfunctional monomer can be used singly or in combination of two or more.

The amount of polyfunctional monomer to be used varies depending on its molecular weight, number of functional groups, etc., but usually, it is appropriate to be in the range of 0.01 to 3.0 parts by weight based on 100 parts by weight of the monomer component constituting the polymer contained in the pressure-sensitive adhesive layer. Do. In some embodiments, the amount of the polyfunctional monomer to be used with respect to 100 parts by weight of the monomer component may be, for example, 0.02 parts by weight or more, 0.1 parts by weight or more, 0.5 parts by weight or more, 1.0 parts by weight or more, or 2.0. It may be not less than parts by weight. With an increase in the amount of the polyfunctional monomer used, a higher cohesive force tends to be obtained. On the other hand, from the viewpoint of avoiding deterioration of the adhesiveness between the pressure-sensitive adhesive layer and the adjacent layer due to excessive cohesiveness, the amount of the polyfunctional monomer to 100 parts by weight of the monomer component may be, for example, 10 parts by weight or less, It may be 5.0 parts by weight or less, or 3.0 parts by weight or less.

(Acrylic oligomer)

The acrylic oligomer can be contained in the A layer from the viewpoint of improving cohesive strength or improving adhesion to a surface adjacent to the pressure-sensitive adhesive layer (for example, it may be a surface of a support). As the acrylic oligomer, those having a higher Tg relative to the Tg of the polymer (eg, acrylic polymer) contained in the pressure-sensitive adhesive layer can be preferably employed.

The Tg of the acrylic oligomer is not particularly limited, and may be, for example, about 20° C. or more and 300° C. or less. The Tg may be, for example, about 30°C or higher, about 40°C or higher, about 60°C or higher, or about 80°C or higher or about 100°C or higher. When the Tg of the acrylic oligomer is increased, the effect of improving the cohesive force tends to be substantially increased. In addition, from the viewpoint of impinging property to the support, shock absorption, and the like, the Tg of the acrylic oligomer may be, for example, about 250°C or less, about 200°C or less, or about 180°C or less or about 150°C or less. In addition, the Tg of the acrylic oligomer is a value calculated based on the formula of Fox in the same manner as the Tg of the acrylic polymer corresponding to the composition of the monomer component.

The Mw of the acrylic oligomer may be typically about 1000 or more and less than about 30000, preferably about 1500 or more and less than about 10000, and more preferably about 2000 or more and less than about 5000. When Mw is within the above range, the effect of improving cohesiveness and adhesion to adjacent surfaces is easily exhibited. Mw of the acrylic oligomer is measured by gel permeation chromatography (GPC), and can be obtained as a value in terms of standard polystyrene. Specifically, it is measured under the conditions of a flow rate of about 0.5 mL/min in a tetrahydrofuran solvent, using TSKgelGMH-H(20) x 2 as a column in HPLC8020 manufactured by Tosoh Corporation.

As a monomer component constituting an acrylic oligomer, various (meth)acrylic acid C _1-20 alkyl esters described above; The above-described various alicyclic hydrocarbon group-containing (meth)acrylates; The above-described various aromatic hydrocarbon group-containing (meth)acrylates; (Meth)acrylate obtained from terpene compound derivative alcohol; (Meth)acrylate monomers such as are mentioned. These can be used alone or in combination of two or more.

The acrylic oligomer is an alkyl (meth)acrylate in which an alkyl group such as isobutyl (meth)acrylate or t-butyl (meth)acrylate has a branched structure; Alicyclic hydrocarbon group-containing (meth)acrylate and aromatic hydrocarbon group-containing (meth)acrylate; It is preferable from the viewpoint of improving adhesiveness that an acrylic monomer having a relatively bulky structure, represented by the like, is contained as a monomer unit. In addition, when ultraviolet rays are used in the synthesis of the acrylic oligomer or in the production of the pressure-sensitive adhesive layer, a monomer having a saturated hydrocarbon group at the ester end is preferable because it is difficult to induce polymerization. For example, the alkyl group has a branched structure. (Meth)acrylate or a saturated alicyclic hydrocarbon group-containing (meth)acrylate can be preferably used.

The proportion of the (meth)acrylate monomer to the total monomer components constituting the acrylic oligomer is typically more than 50% by weight, preferably 60% by weight or more, more preferably 70% by weight or more (e.g. 80 It is weight% or more, and further 90 weight% or more). In a preferred embodiment, the acrylic oligomer has a monomer composition consisting of substantially only one or two or more (meth)acrylate monomers. When the monomer component contains an alicyclic hydrocarbon group-containing (meth)acrylate and a (meth)acrylic acid C _1-20 alkyl ester, their weight ratio is not particularly limited, for example, in the range of 10/90 to 90/10, It can be set as the range of 20/80-80/20, the range of 70/30-30/70, etc.

As the constituent monomer component of the acrylic oligomer, in addition to the (meth)acrylate monomer described above, a functional group-containing monomer can be used if necessary. Examples of the functional group-containing monomer include monomers having a nitrogen atom-containing heterocycle such as N-vinyl-2-pyrrolidone and N-acryloylmorpholine; Amino group-containing monomers such as N,N-dimethylaminoethyl (meth)acrylate; Amide group-containing monomers such as N,N-diethyl (meth)acrylamide; Carboxy group-containing monomers, such as AA and MAA; Hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate; Can be mentioned. These functional group-containing monomers can be used alone or in combination of two or more. In the case of using a functional group-containing monomer, the ratio of the functional group-containing monomer to the total monomer components constituting the acrylic oligomer can be, for example, 1% by weight or more, 2% by weight or more, or 3% by weight or more. For example, it can be 15 weight% or less, 10 weight% or less, or 7 weight% or less.

Preferred acrylic oligomers include, for example, dicyclopentanyl methacrylate (DCPMA), cyclohexyl methacrylate (CHMA), isobornyl methacrylate (IBXMA), isobornyl acrylate (IBXA), dicyclo In addition to each homopolymer of fentanyl acrylate (DCPA), 1-adamantyl methacrylate (ADMA), and 1-adamantyl acrylate (ADA), a copolymer of DCPMA and MMA, a copolymer of DCPMA and IBXMA, ADA And methyl methacrylate (MMA), CHMA and isobutyl methacrylate (IBMA) copolymer, CHMA and IBXMA copolymer, CHMA and acryloylmorpholine (ACMO) copolymer, CHMA and di A copolymer of ethyl acrylamide (DEAA), a copolymer of CHMA and AA, etc. are mentioned.

The acrylic oligomer can be formed by polymerizing the constituent monomer components. The polymerization method and the polymerization mode are not particularly limited, and various conventionally known polymerization methods (eg, solution polymerization, emulsion polymerization, bulk polymerization, photopolymerization, radiation polymerization, etc.) can be adopted as appropriate modes. The types of polymerization initiators (e.g., azo polymerization initiators) that can be used as needed are generally as exemplified for the synthesis of acrylic polymers, and the amount of polymerization initiators and chain transfer agents (e.g., mercaptans The amount of) is appropriately set based on common technical knowledge so as to obtain a desired molecular weight, and thus a detailed description is omitted.

When the acrylic oligomer is contained in the layer A, the content may be, for example, 0.01 parts by weight or more with respect to 100 parts by weight of the monomer component constituting the polymer (typically acrylic polymer) contained in the layer A. , From the viewpoint of obtaining a higher effect, it may be 0.05 parts by weight or more, or 0.1 parts by weight or more or 0.2 parts by weight or more. In addition, from the viewpoint of compatibility with the polymer, the content of the acrylic oligomer is usually less than 50 parts by weight, preferably less than 30 parts by weight, more preferably 25 parts by weight or less, For example, it may be 10 parts by weight or less, 5 parts by weight or less, or 1 part by weight or less.

(Adhesive imparting resin)

The layer A may contain a tackifying resin. As tackifying resin, for example, a petroleum-based tackifying resin, terpene-based tackifying resin, phenolic tackifying resin, ketone-based tackifying resin, etc., including rosin-based tackifying resin and rosin derivative tackifying resin. Can be lifted. These can be used alone or in combination of two or more.

As the rosin-based tackifying resin, for example, in addition to rosin such as gum rosin, wood rosin, tall oil rosin, stabilized rosin (for example, stabilized rosin obtained by disproportionation or hydrogenation of the rosin), polymerized rosin ( For example, a multimer of the above rosin, typically a dimer), modified rosin (e.g., unsaturated acid-modified rosin modified with unsaturated acids such as maleic acid, fumaric acid, (meth)acrylic acid, etc.), etc. I can.

Examples of the rosin derivative tackifying resin include esterified products of the rosin-based tackifying resin (for example, rosin esters such as stabilized rosin ester and polymerized rosin ester), and phenol-modified products of the rosin-based resin ( Phenol-modified rosin) and its esterified product (phenol-modified rosin ester).

Examples of the petroleum tackifying resin include aliphatic petroleum resins, aromatic petroleum resins, copolymerized petroleum resins, alicyclic petroleum resins, and hydrides thereof.

Examples of the terpene tackifying resin include α-pinene resin, β-pinene resin, aromatic modified terpene resin, terpenephenol resin, and the like.

Examples of the ketone-based tackifying resin include ketones (e.g., aliphatic ketones such as methyl ethyl ketone, methyl isobutyl ketone and acetophenone; alicyclic ketones such as cyclohexanone and methylcyclohexanone) Ketone resins obtained by condensation of and formaldehyde; And the like.

In some aspects of the pressure-sensitive adhesive sheet disclosed herein, as the tackifying resin, one or two or more selected from rosin-based tackifying resins, rosin derivative tackifying resins, and terpenephenol resins can be preferably used. . Among them, a rosin derivative tackifying resin is preferred, and preferred examples thereof include rosin esters such as stabilized rosin esters and polymerized rosin esters.

In the water-dispersible pressure-sensitive adhesive composition, it is preferable to use a water-dispersible tackifier resin in a form in which the tackifying resin as described above is dispersed in an aqueous solvent. For example, by mixing an aqueous dispersion of an acrylic polymer and a water-dispersible tackifying resin, a pressure-sensitive adhesive composition containing these components in a desired ratio can be easily prepared. In some aspects, as the water-dispersible tackifying resin, from the viewpoint of consideration for environmental hygiene and the like, those that do not substantially contain at least an aromatic hydrocarbon-based solvent can be preferably used. It is more preferable to use a water-dispersible tackifier resin that does not substantially contain an aromatic hydrocarbon-based solvent or other organic solvent.

As a commercial item of the water-dispersible tackifying resin containing rosin esters, for example, the brand names "Super Ester E-720", "Super Ester E-730-55" manufactured by Arakawa Chemical Co., Ltd., "Super Ester E-865NT" '', ``Pencel D-125'', ``Pencel D-135'', ``Pencel D-160'', etc., as well as the brand names ``Hariester SK-90D'', ``Hariester SK-70D'', ``Hariester'' manufactured by Harima Hwasung Co., Ltd. SK-70E", "Neotol 115E", etc. are mentioned. In addition, as a commercial product of terpenephenol resin (which may be in the form of a water-dispersible terpenephenol resin), Arakawa Chemical Industries Co., Ltd. trade names "Tamanol E-100", "Tamanol E-200", and "Tamanol E -200NT" etc. are mentioned.

The softening point of the tackifying resin is not particularly limited. From the viewpoint of suppressing the decrease in the cohesive force of the pressure-sensitive adhesive layer, usually, a tackifying resin having a softening point of 80°C or higher can be preferably used. The softening point of the tackifying resin may be 90°C or higher, 100°C or higher, 110°C or higher, or 120°C or higher. A tackifying resin having a softening point of 130°C or higher or 140°C or higher may be used. Further, from the viewpoint of transparency and adhesion to an adherend, a tackifying resin having a softening point of 200°C or less or 180°C or less can be preferably used. In addition, as the softening point of the tackifying resin referred to herein, a nominal value described in literature, catalog, or the like can be adopted. When there is no nominal value, the softening point of the tackifying resin can be measured based on the softening point test method (ring ball method) specified in JIS K5902 or JIS K2207.

The amount of tackifying resin to be used is preferably 1 part by weight or more based on 100 parts by weight of the monomer component constituting the polymer contained in the layer A from the viewpoint of exhibiting the effect of use preferably, and 5 parts by weight It may be more than, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, or 25 parts by weight or more. In addition, from the viewpoint of balancing the adhesion and cohesiveness to the adherend, the amount of tackifying resin to 100 parts by weight of the monomer component may be, for example, 70 parts by weight or less, 50 parts by weight or less, and 40 parts by weight. It may be negative. Alternatively, it may be a layer A that does not contain a tackifying resin substantially.

The pressure-sensitive adhesive sheet according to some aspects can further improve water resistance reliability by performing a treatment to increase the water peeling force at a desired timing. The pressure-sensitive adhesive sheet exhibiting such properties can be realized, for example, in a configuration in which the layer A contains a tackifying resin, but is not limited to such a configuration. The treatment to increase the water peeling force may be, for example, a treatment in which a temperature higher than the room temperature range is applied after affixing the pressure-sensitive adhesive sheet to the adherend. The temperature to be applied is not particularly limited, and can be selected in consideration of workability, economy, convenience, heat resistance of an adhesive sheet or an adherend, and the like. The temperature may be 45°C or higher, or 55°C or higher, for example. In addition, the temperature may be, for example, less than 150°C, 120°C or less, 100°C or less, and 80°C or less. The time for applying the above temperature is not particularly limited, and for example, it may be 1 hour or more, 3 hours or more, or 1 day or more. Alternatively, the temperature may be applied over a longer period of time as long as no significant thermal deterioration occurs in the pressure-sensitive adhesive sheet or adherend. In some aspects, from the viewpoint of improving the efficiency of the treatment, the time to apply the temperature may be, for example, within 14 days or within 7 days. The temperature may be applied at one time or may be applied by dividing into a plurality of times.

Even if the water peeling force (N3) of the adhesive sheet after the treatment to increase the water peeling force is, for example, twice or more with respect to the water peeling force (N2) measured by the method described above with respect to the adhesive sheet It may be 5 times or more, 10 times or more, 20 times or more, and 30 times or more. The water peeling force (N3) may be, for example, 2.0 N/10 mm or more, 3.0 N/10 mm or more, or 4.0 N/10 mm or more. In addition, the measurement of the water peeling force (N3) was carried out in the same manner as the measurement of the water peeling force (N2) described above, except that the treatment to increase the water peeling force was performed on the sample for evaluation taken out from the autoclave. do.

The pressure-sensitive adhesive composition used for forming the layer A may, if necessary, contain an acid or a base (such as aqueous ammonia) used for the purpose of adjusting pH or the like. Other optional components that may be contained in the composition include viscosity modifiers (e.g., thickeners), leveling agents, plasticizers, fillers, coloring agents such as pigments and dyes, stabilizers, preservatives, anti-aging agents, etc., in the field of adhesive compositions. Various general additives are illustrated. For such various additives, conventionally known additives can be used by conventional methods, and since they do not particularly characterize the present invention, detailed descriptions are omitted.

(2) B layer

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet disclosed herein may further include a layer B disposed on the rear side of the layer A in addition to the layer A constituting at least one surface of the pressure-sensitive adhesive layer. According to the configuration including the layer A and the layer B as described above, for example, the bulk properties of the pressure-sensitive adhesive layer by the layer B while imparting good water peelability by the layer A (e.g., water resistance, cohesiveness, heat resistance, etc. ) Can be adjusted. Therefore, according to the pressure-sensitive adhesive layer comprising the layer A and the layer B, it is easy to obtain a pressure-sensitive adhesive sheet having good water peeling property and excellent water resistance reliability. For example, a pressure-sensitive adhesive sheet having a low water-resistant adhesion reduction rate and a high water peel adhesion reduction rate (and/or a long water entry distance) can be preferably realized. Further, for example, a pressure-sensitive adhesive sheet having both strong adhesiveness and good water peelability at a high level can be preferably realized.

The layer B may be disposed in direct contact with the back surface of the layer A, or may be disposed between the back surface of the layer A and the other layer. The other layer (hereinafter, also referred to as an intermediate layer) is typically a non-adhesive layer, and for example, a plastic film, foam sheet, woven or nonwoven fabric, paper, metal foil, and the like similar to those of the support described later can be used. From the viewpoint of the flexibility of the pressure-sensitive adhesive sheet or the followability of the surface shape of the adherend, in some embodiments, a pressure-sensitive adhesive layer having a structure in which the layer A and the layer B are directly in contact (that is, without interposing an intermediate layer) is preferably used. Can be adopted.

Layer B is one or two selected from various known adhesives such as acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, polyether-based pressure-sensitive adhesives, polyamide-based pressure-sensitive adhesives, and fluorine-based pressure-sensitive adhesives. It may be a pressure-sensitive adhesive layer comprising more than one type of pressure-sensitive adhesive. From the viewpoints of transparency and weather resistance, in some aspects, an acrylic pressure-sensitive adhesive can be preferably used as a constituent material of the layer B. The acrylic pressure-sensitive adhesive constituting the layer B is, for example, exemplified as an acrylic pressure-sensitive adhesive that can be used for the layer A, and can be selected so that desired properties are exhibited in combination with the layer A. The layer B may have a single-layer structure consisting of one layer, or a multilayer structure including two or more layers having different compositions.

In some embodiments, the monomer component constituting the polymer (eg, acrylic polymer) contained in the layer B contains C _1-20 (meth) acrylate alkyl ester in a proportion of 40% by weight or more of the total monomer component. Can include. The proportion of C _1-20 (meth) acrylate alkyl ester in the entire monomer component of the layer B may be, for example, 98% by weight or less, or 95% by weight or less from the viewpoint of improving the cohesiveness of the layer B, or 85% by weight. It may be as follows, 70 weight% or less may be sufficient, and 60 weight% or less may be sufficient.

The monomer component constituting the layer B may contain a copolymerizable monomer together with an alkyl (meth)acrylate ester. The copolymerizable monomer can be appropriately selected from those exemplified as the copolymerizable monomer that can be used for the layer A. The amount of the copolymerizable monomer to be used may be, for example, 5% by weight or more, 15% by weight or more, 30% by weight or more, or 40% by weight or more of the entire monomer component constituting the layer B.

In some aspects, the proportion of the carboxy group-containing monomer in the monomer component constituting the layer B may be, for example, 2% by weight or less, 1% by weight or less, or 0.5% by weight or less. It is not necessary to substantially use a carboxyl group-containing monomer as a monomer component constituting the layer B. Here, that the carboxy group-containing monomer is not used substantially means that the carboxy group-containing monomer is not used intentionally at least. The pressure-sensitive adhesive sheet having the layer B having such a composition is preferable because it tends to have high water resistance reliability.

As a suitable example of a pressure-sensitive adhesive sheet comprising a layer A and a layer B, the gel fraction of the layer B is higher than that of the layer A, and the swelling degree of the layer B satisfies one or both of the lower swelling degree of the layer A. The adhesive sheet provided with the said adhesive layer is mentioned. According to such a configuration, it is easy to obtain a pressure-sensitive adhesive sheet having a low water-resistant adhesive strength reduction rate and a high water peel adhesion reduction ratio (and/or a long water entry distance).

In some embodiments, the layer B may be a layer formed from a photo-curable pressure-sensitive adhesive composition or a solvent-type pressure-sensitive adhesive composition. According to the layer B formed from such a composition, it is easy to obtain a pressure-sensitive adhesive sheet having good water resistance reliability. For example, in a combination of a layer A formed from a water-dispersible pressure-sensitive adhesive composition and a layer B formed from a photo-curable pressure-sensitive adhesive composition, or a combination of a layer A formed from a water-dispersible pressure-sensitive adhesive composition and a layer B formed from a solvent-type pressure-sensitive adhesive composition, water-resistant adhesive strength A pressure-sensitive adhesive sheet having a low reduction rate and a high water peel adhesion reduction rate (and/or a long water entry distance) can be preferably realized. In some aspects, from the viewpoint of improving water resistance, a layer B substantially free of a water affinity agent can be preferably employed.

<Support>

The pressure-sensitive adhesive sheet according to some aspects may be in the form of a pressure-sensitive adhesive sheet with a support including a support bonded to the other surface (back) of the pressure-sensitive adhesive layer. The material of the support is not particularly limited, and can be appropriately selected according to the purpose of use of the pressure-sensitive adhesive sheet or the mode of use. Non-limiting examples of the support that can be used include polyolefin films based on polyolefins such as polypropylene and ethylene-propylene copolymers, polyester films based on polyesters such as polyethylene terephthalate and polybutylene terephthalate, Plastic films such as polyvinyl chloride films containing polyvinyl chloride as a main component; Foam sheets made of foams such as polyurethane foam, polyethylene foam, and polychloroprene foam; Woven fabrics and non-woven fabrics made of a variety of fibrous substances (natural fibers such as hemp and cotton, synthetic fibers such as polyester and vinylon, semi-synthetic fibers such as acetate, etc.); Paper, such as Japanese paper, fine-quality paper, graft paper, and crepe paper; Metal foils such as aluminum foil and copper foil; And the like. It may be a support having a structure in which these are combined. Examples of the support of such a composite structure include, for example, a support having a structure in which a metal foil and the plastic film are laminated, and a plastic sheet reinforced with inorganic fibers such as glass cloth.

Various films (hereinafter, also referred to as support films) can be preferably used as a support for the pressure-sensitive adhesive sheet disclosed here. The support film may be a porous film, such as a foam film or a nonwoven fabric sheet, may be a non-porous film, or may be a film having a structure in which a porous layer and a non-porous layer are laminated. In some aspects, as the support film, one containing a resin film (self-standing or non-dependent) capable of maintaining its shape independently can be preferably used as a base film. Here, the "resin film" is a non-porous structure and typically means a (voidless) resin film that does not contain substantially any air bubbles. Therefore, the resin film is a concept distinguished from a foam film or a nonwoven fabric. The resin film may have a single-layer structure or a multilayer structure of two or more layers (eg, a three-layer structure).

As the resin material constituting the resin film, for example, polycycloolefin derived from a monomer having an aliphatic ring structure such as polyester, polyolefin, norbornene structure, nylon 6, nylon 66, partially aromatic polyamide, etc. Polyamide (PA), polyimide (PI), polyamideimide (PAI), polyetheretherketone (PEEK), polyethersulfone (PES), polyphenylene sulfide (PPS), polycarbonate (PC), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), polystyrene, polyvinyl chloride, polyvinylidene chloride, fluorine resin such as polytetrafluoroethylene (PTFE), acrylic resin such as polymethyl methacrylate, diacetyl Resins such as cellulose polymers such as cellulose and triacetyl cellulose, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, and epoxy polymers can be used. The resin film may be formed using a resin material containing one type of such a resin alone, or may be formed using a resin material in which two or more types are blended. The resin film may be unstretched or stretched (for example, uniaxially stretched or biaxially stretched).

As suitable examples of the resin material constituting the resin film, a polyester resin, a PPS resin, and a polyolefin resin can be mentioned. Here, the polyester resin refers to a resin containing polyester in a proportion exceeding 50% by weight. Similarly, PPS resin refers to a resin containing PPS in a proportion exceeding 50% by weight, and a polyolefin resin refers to a resin containing polyolefin in a proportion exceeding 50% by weight.

As the polyester resin, typically, a polyester resin containing as a main component polyester obtained by polycondensing a dicarboxylic acid and a diol is used. As a specific example of a polyester resin, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate, etc. are mentioned.

As the polyolefin resin, one type of polyolefin may be used alone, or two or more types of polyolefin may be used in combination. The polyolefin may be, for example, a homopolymer of α-olefin, a copolymer of two or more α-olefins, a copolymer of one or two or more α-olefins and other vinyl monomers. Specific examples include ethylene-propylene copolymers such as polyethylene (PE), polypropylene (PP), poly-1-butene, poly-4-methyl-1-pentene, and ethylene propylene rubber (EPR), and ethylene-propylene- Butene copolymers, ethylene-butene copolymers, ethylene-vinyl alcohol copolymers, and ethylene-ethyl acrylate copolymers. Any of low density (LD) polyolefin and high density (HD) polyolefin can be used. Examples of polyolefin resin films include non-stretched polypropylene (CPP) films, biaxially stretched polypropylene (OPP) films, low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, and medium-density polyethylene (MDPE) films. , A high-density polyethylene (HDPE) film, a polyethylene (PE) film obtained by blending two or more types of polyethylene (PE), and a PP/PE blend film obtained by blending polypropylene (PP) and polyethylene (PE).

As a specific example of the resin film which can be used preferably as a support, a PET film, a PEN film, a PPS film, a PEEK film, a CPP film, and an OPP film are mentioned. Preferred examples in terms of strength include PET film, PEN film, PPS film, and PEEK film. A PET film is mentioned as a preferable example from the viewpoint of availability, dimensional stability, optical properties, and the like.

In the resin film, known additives such as light stabilizers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), fillers, slip agents, and anti-blocking agents can be blended as necessary. The blending amount of the additive is not particularly limited, and can be appropriately set according to the use of the pressure-sensitive adhesive sheet.

The production method of the resin film is not particularly limited. For example, conventionally known general resin film molding methods, such as extrusion molding, inflation molding, T die cast molding, and calender roll molding, can be appropriately adopted.

The support may be formed substantially from such a resin film. Alternatively, the support may include an auxiliary layer other than the resin film. Examples of the auxiliary layer include an optical property adjustment layer (e.g., a colored layer, an antireflection layer), a printing layer or a laminate layer, an antistatic layer, an undercoat layer, a peeling layer, etc. for imparting a desired appearance to a support or an adhesive sheet. A surface treatment layer is mentioned. Moreover, the said support material may be an optical member mentioned later.

The thickness of the support is not particularly limited, and can be selected according to the purpose of use of the pressure-sensitive adhesive sheet or the mode of use. The thickness of the support may be, for example, 1000 µm or less, 500 µm or less, 100 µm or less, 70 µm or less, 50 µm or less, 25 µm or less, 10 µm or less, It may be 5 µm or less. When the thickness of the support is reduced, the flexibility of the pressure-sensitive adhesive sheet and the followability to the surface shape of the adherend tend to be improved. In addition, from the viewpoint of handling properties and workability, the thickness of the support may be, for example, 2 µm or more, or more than 5 µm or 10 µm. In some aspects, the thickness of the support may be, for example, 20 µm or more, 35 µm or more, or 55 µm or more.

On the side of the support to be bonded to the pressure-sensitive adhesive layer, if necessary, conventionally known corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, application of a primer (primer), antistatic treatment, etc. Surface treatment may be performed. Such surface treatment may be a treatment for improving the adhesion between the support and the pressure-sensitive adhesive layer, in other words, the seepage property of the pressure-sensitive adhesive layer to the support. The composition of the primer is not particularly limited and can be appropriately selected from known ones. The thickness of the undercoat layer is not particularly limited, but usually about 0.01 µm to 1 µm is suitable, and about 0.1 µm to 1 µm is preferable.

On the side of the support opposite to the side to be bonded to the pressure-sensitive adhesive layer (hereinafter, also referred to as the back side), as necessary, a conventionally known surface treatment such as peeling treatment, adhesion or adhesion improvement treatment, antistatic treatment, etc. is performed. It may be. For example, by surface-treating the back surface of the support with a release treatment agent, the rewinding force of the adhesive sheet wound in a roll shape can be lightened. As the release treatment agent, a silicone release treatment agent, a long-chain alkyl release treatment agent, an olefin release treatment agent, a fluorine release treatment agent, a fatty acid amide release treatment agent, molybdenum sulfide, silica powder, or the like can be used.

<Adhesive sheet>

The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet disclosed herein may be a cured layer of the pressure-sensitive adhesive composition. That is, the pressure-sensitive adhesive layer can be formed by appropriately performing a curing treatment after applying (for example, applying) the pressure-sensitive adhesive composition to an appropriate surface. When performing two or more types of curing treatments (drying, crosslinking, polymerization, etc.), these can be performed simultaneously or over multiple steps. In a pressure-sensitive adhesive composition using a partial polymer (acrylic polymer syrup) of a monomer component, a final copolymerization reaction is typically performed as the curing treatment. That is, the partial polymer is subjected to an additional copolymerization reaction to form a complete polymer. For example, if it is a photocurable adhesive composition, light irradiation is performed. If necessary, curing treatment such as crosslinking and drying may be performed. For example, when it is necessary to dry with a photocurable pressure-sensitive adhesive composition, photocuring may be performed after drying. In the pressure-sensitive adhesive composition using a completely polymerized product, treatment such as drying (heat drying) and crosslinking is typically performed as the curing treatment, if necessary. The pressure-sensitive adhesive layer having a multilayered structure of two or more layers can be produced by bonding the previously formed pressure-sensitive adhesive layers. Alternatively, a pressure-sensitive adhesive composition may be applied onto the first pressure-sensitive adhesive layer formed in advance, and the pressure-sensitive adhesive composition may be cured to form a second pressure-sensitive adhesive layer.

The application of the pressure-sensitive adhesive composition can be performed using a conventional coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, and a spray coater. In the pressure-sensitive adhesive sheet having a support, as a method of forming the pressure-sensitive adhesive layer on the support, a direct method of forming the pressure-sensitive adhesive layer by directly applying the pressure-sensitive adhesive composition to the support may be used, or the pressure-sensitive adhesive layer formed on the release surface may be used as a support. You may use a transfer method to transfer to.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and may be, for example, about 3 μm to 1000 μm. From the viewpoint of increasing the water resistance reliability by bringing the pressure-sensitive adhesive layer into close contact with the adherend, in some embodiments, the thickness of the pressure-sensitive adhesive layer may be, for example, 5 μm or more, 10 μm or more, 20 μm or more, and 30 It may be greater than or equal to 50 μm, greater than or equal to 50 μm, greater than or equal to 50 μm, greater than or equal to 70 μm, greater than or equal to 100 μm, or greater than or equal to 120 μm. In addition, from the viewpoint of preventing the occurrence of glue retention due to cohesive failure of the pressure-sensitive adhesive layer, in some aspects, the thickness of the pressure-sensitive adhesive layer may be, for example, 500 μm or less, 300 μm or less, and 200 μm or less. It may be sufficient, and 170 micrometers or less may be sufficient as it. The technique disclosed herein can also be preferably implemented in the form of a pressure-sensitive adhesive sheet having a thickness of the pressure-sensitive adhesive layer of 130 μm or less, 90 μm or less, 60 μm or less, or 40 μm or less. In addition, in the pressure-sensitive adhesive layer made of the layer A, the thickness of the pressure-sensitive adhesive layer means the thickness of the layer A.

When the pressure-sensitive adhesive layer becomes thick, in general, there is a tendency that both water peeling property and water resistance reliability become difficult. From this point of view, in an aspect in which the thickness of the pressure-sensitive adhesive layer is more than 50 μm, for example, a configuration in which the pressure-sensitive adhesive layer includes the layer A and the layer B can be preferably adopted. According to the pressure-sensitive adhesive layer having such a configuration, even if the pressure-sensitive adhesive layer is thick, it is easy to obtain a pressure-sensitive adhesive sheet that achieves high level of water peelability and water resistance reliability.

In the aspect in which the pressure-sensitive adhesive layer includes layer A and layer B, the thickness of layer A may be, for example, 1 μm or more, 2 μm or more, 4 μm or more, 5 μm or more, or 10 μm. It may be more than or equal to 15 µm or more. Moreover, the thickness of the layer A may be, for example, 50 µm or less, 45 µm or less, 35 µm or less, and 25 µm or less. Particularly, in an embodiment including a layer A formed from a water-dispersible pressure-sensitive adhesive composition or an embodiment in which the layer A contains a water affinity agent, the thickness of the layer A is not too large, improving the water resistance reliability of the pressure-sensitive adhesive sheet and the transparency of the pressure-sensitive adhesive layer. It is preferable from the viewpoint of improvement of.

In the aspect in which the pressure-sensitive adhesive layer includes the layer A and the layer B, the thickness of the layer B may be, for example, 5 µm or more, or 10 µm or more. From the viewpoint of better exerting the effect of forming the layer B on the back side of the layer A, in some aspects, the thickness of the layer B may be, for example, 20 μm or more, or 30 μm or more, It may be 50 µm or more, 70 µm or more, or 100 µm or more.

In the aspect in which the pressure-sensitive adhesive layer includes the layer A and the layer B, the thickness of the layer A occupied by the entire thickness of the pressure-sensitive adhesive layer may be, for example, 90% or less, usually preferably 70% or less, and even 50% or less. It may be, 30% or less, 20% or less may be sufficient, and 15% or less may be sufficient. In addition, from the viewpoint of the ease of formation of the layer A and the water peelability of the pressure-sensitive adhesive sheet, in some aspects, the thickness of the layer A occupied by the entire thickness of the pressure-sensitive adhesive layer may be, for example, 3% or more, or even 5% or more. It may be, 7% or more may be sufficient, and 10% or more may be sufficient.

<use>

The pressure-sensitive adhesive sheet disclosed herein has good rework properties in that it can be easily peeled off from an adherend using an aqueous liquid such as water, and has good water resistance reliability. For example, various portable devices (portable Devices), automobiles, home appliances, and the like, and can be used for fixing, bonding, molding, decoration, protection, support, etc. of the member. The material constituting at least the surface of the member is, for example, glass such as an alkali glass plate or an alkali free glass; Resin film; Metal materials such as stainless steel (SUS) and aluminum; Resin materials such as acrylic resin, ABS resin, polycarbonate resin, and polystyrene resin; Etc. The pressure-sensitive adhesive sheet disclosed herein is coated with a paint such as acrylic, polyester, alkyd, melamine, urethane, acid-epoxy crosslinked, or composites thereof (for example, acrylic melamine, alkyd melamine). It may be affixed to a surface or a plated surface such as a galvanized steel sheet. The pressure-sensitive adhesive sheet disclosed herein may be, for example, a component of the pressure-sensitive adhesive sheet attachment member in which such a member is bonded to the layer A side of the pressure-sensitive adhesive sheet.

In such an adhesive sheet attaching member, the surface of the member in contact with the adhesive layer (hereinafter, also referred to as a bonding surface) has a contact angle with distilled water of, for example, 60 degrees or less, preferably 50 degrees or less. It may be a surface showing a degree of hydrophilicity. In some aspects, the contact angle of the bonding surface may be, for example, 45 degrees or less, 40 degrees or less, 35 degrees or less, and 30 degrees or less. When the contact angle of the bonding surface becomes small, water tends to wet and spread along the bonding surface, and the water peelability of the adhesive sheet tends to be improved. This is preferable from the viewpoint of improving the rework property when attaching the adhesive sheet to the bonding surface to produce a member with an adhesive sheet. In addition, if the contact angle of the bonding surface is at least at the time of bonding the pressure-sensitive adhesive sheet (for example, 30 minutes before bonding) or less than any of the above-described angles, the effect of improving the rework property is exhibited by the contact angle being less than or equal to a predetermined value. Can be. In principle, the lower limit of the contact angle is 0 degrees. In some aspects, the contact angle of the bonding surface may exceed 0 degrees, may be 1 degrees or more, 3 degrees or more, or 5 degrees or more. The contact angle of the bonding surface of the member is measured in the same manner as the contact angle of the alkali glass plate described above.

The bonding surface of the member may be subjected to a hydrophilic treatment in order to reduce the contact angle with distilled water. Examples of the hydrophilic treatment include treatments that contribute to the improvement of hydrophilicity, such as corona treatment, plasma treatment, and hydrophilic coating treatment for forming a hydrophilic coating layer. The apparatus and treatment conditions used for corona treatment or plasma treatment can be set so that a bonding surface showing a desired contact angle is obtained based on a conventionally known technique. Formation of the hydrophilic coating layer can be carried out by appropriately selecting what obtains a bonding surface exhibiting a desired contact angle from a known coating agent, and using a conventional method. The thickness of the hydrophilic coating layer may be, for example, 0.01 µm or more, 0.05 µm or more, or 0.1 µm or more, and may be, for example, 10 µm or less, 5 µm or less, or 2 µm or less.

As an example of a preferable application, an optical application is mentioned. More specifically, for example, as an optical adhesive sheet used for bonding an optical member (for bonding an optical member) or for manufacturing a product (optical product) in which the optical member is used, the adhesive disclosed herein A sheet can be preferably used.

The said optical member refers to a member having optical properties (eg, polarization, light refraction, light scattering, light reflectivity, light transmittance, light absorption, light diffraction, optical rotation, visibility, etc.). The optical member is not particularly limited as long as it is a member having optical properties. For example, a member constituting devices (optical devices) such as a display device (image display device) and an input device, or a member used in these devices For example, a polarizing plate, a wave plate, a retardation plate, an optical compensation film, a luminance enhancing film, a light guide plate, a reflective film, an antireflection film, a hard coat (HC) film, a shock absorbing film, an antifouling film, a photochromic Film, light control film, transparent conductive film (ITO film), design film, decorative film, surface protection plate, prism, lens, color filter, transparent substrate, and furthermore, members on which they are laminated (collectively referred to as ``functional film'' There are cases.), etc. are mentioned. In addition, the above-mentioned "plate" and "film" shall each include forms such as a plate shape, a film shape, and a sheet shape, and for example, a "polarization film" refers to a "polarizing plate", a "polarizing sheet", etc. It shall be included.

Examples of the display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), and electronic paper. Moreover, a touch panel etc. are mentioned as said input device.

Although it does not specifically limit as said optical member, For example, a member made of glass, acrylic resin, polycarbonate, polyethylene terephthalate, metal thin film, etc. (e.g., a sheet-like member, a film-like member, a plate-like member) etc. are mentioned. I can. In addition, the "optical member" in this specification also includes a member (design film, decorative film, surface protection film, etc.) that plays a role of decoration or protection while maintaining visibility of a display device or an input device. It should be done.

Although it does not specifically limit as an aspect of bonding an optical member using the adhesive sheet disclosed here, For example, (1) An aspect of bonding optical members through the adhesive sheet disclosed here, and (2) ) An optical member may be attached to a member other than the optical member via the adhesive sheet disclosed herein, and (3) the adhesive sheet disclosed herein includes an optical member, and the adhesive sheet is an optical member or an optical member. It may be an aspect to be attached to members other than the member. In addition, in the aspect of the above (3), the pressure-sensitive adhesive sheet including an optical member may be, for example, a pressure-sensitive adhesive sheet whose support is an optical member (eg, an optical film). In this way, the pressure-sensitive adhesive sheet including an optical member as a support can be regarded as a pressure-sensitive adhesive optical member (eg, a pressure-sensitive optical film). In addition, when the pressure-sensitive adhesive sheet disclosed herein is a type of pressure-sensitive adhesive sheet having a support, and the functional film is used as the support, the pressure-sensitive adhesive sheet disclosed herein is a pressure-sensitive adhesive layer disclosed here on at least one side of the functional film. It can also be grasped as a "adhesive functional film" having.

<Peeling method>

According to this specification, a method for peeling a pressure-sensitive adhesive sheet attached to an adherend is provided. The peeling method, in a state in which an aqueous liquid exists at an interface between the adherend and the adhesive sheet in the peeling wire of the adhesive sheet from the adherend, follows the movement of the peeling wire, and the interface of the aqueous liquid And a water peeling step of peeling the pressure-sensitive adhesive sheet from the adherend while advancing the entry to the substrate. According to the water peeling step, the adhesive sheet can be peeled from the adherend by effectively using the aqueous liquid. As the aqueous liquid, water or a mixed solvent containing water as a main component may contain a small amount of additives as necessary. As a solvent other than water constituting the mixed solvent, a lower alcohol (eg ethyl alcohol) or a lower ketone (eg acetone) that can be uniformly mixed with water may be used. As the additive, a known surfactant or the like can be used. From the viewpoint of avoiding contamination of the adherend, in some embodiments, an aqueous liquid substantially free of additives can be preferably used. From the viewpoint of environmental hygiene, it is particularly preferable to use water as the aqueous liquid. The water is not particularly limited, and, for example, distilled water, ion-exchanged water, tap water, etc. can be used in consideration of the purity and availability required depending on the application.

In some aspects, in the peeling method, for example, in the same manner as in the measurement of water peeling force (N2), an aqueous liquid is supplied onto the adherend near the outer edge of the pressure-sensitive adhesive sheet affixed to the adherend, and the After the aqueous liquid enters the interface between the adhesive sheet and the adherend from the outer edge of the pressure-sensitive adhesive sheet, no new water is supplied (i.e., using only the aqueous liquid supplied on the adherend before starting peeling) It can be carried out preferably in an aspect of advancing peeling of. In addition, if water entering the interface between the pressure-sensitive adhesive sheet and the adherend is likely to be depleted in the middle of the water peeling process, following the movement of the peeling wire, water may be additionally supplied intermittently or continuously after the start of the water peeling process. . For example, in the case where the adherend has water absorption, or when an aqueous liquid tends to remain on the adherend surface or adhesive surface after peeling, the mode of additionally supplying water after the start of the water peeling process can be preferably adopted. .

The amount of the aqueous liquid supplied before the start of peeling is not particularly limited as long as it is an amount capable of introducing the aqueous liquid into the interface between the adhesive sheet and the adherend from outside the affixing range of the adhesive sheet. The amount of the aqueous liquid may be, for example, 5 µL or more, usually 10 µL or more, and may be 20 µL or more. In addition, there is no particular limitation on the upper limit of the amount of the aqueous liquid. In some embodiments, from the viewpoint of improving workability, the amount of the aqueous liquid may be, for example, 10 mL or less, 5 mL or less, 1 mL or less, 0.5 mL or less, and 0.1 mL. It may be less than or equal to 0.05 mL or less. By reducing the amount of the aqueous liquid, it is possible to omit or simplify the operation of removing the aqueous liquid by drying or wiping off the adhesive sheet after peeling.

The operation of injecting an aqueous liquid into the interface between the adhesive sheet and the adherend from the outer edge of the adhesive sheet at the time of initiation of peeling is performed, for example, the tip of a jig such as a cutter knife or a needle into the interface at the outer edge of the adhesive sheet. Inserting the adhesive sheet, lifting the outer edge of the adhesive sheet by scratching it with a hook or fingernail, and lifting the end of the adhesive sheet by attaching a strong adhesive tape or sucker to the back surface near the outer edge of the adhesive sheet, etc. It can be carried out in an aspect. As described above, by forcibly entering the aqueous liquid into the interface from the outer edge of the pressure-sensitive adhesive sheet, a state in which the aqueous liquid is present at the interface between the adherend and the pressure-sensitive adhesive sheet can be efficiently formed. Moreover, good water peelability after the operation of forcibly entering the interface of the aqueous liquid to create an opportunity for peeling, and high water resistance reliability in the case of not performing such an operation can be suitably compatible.

It is preferable that the pressure-sensitive adhesive sheet to be peeled off by the above-described peeling method includes a pressure-sensitive adhesive layer, and the layer A constituting at least the surface of the adherend side of the pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive containing a water affinity agent. It is preferable that the said adhesive sheet is any adhesive sheet disclosed here, for example. Therefore, the said peeling method is preferable as a peeling method of any adhesive sheet disclosed here.

The water peeling process according to some aspects may be preferably carried out in an aspect of moving the peeling wire at a speed of 10 mm/min or more. Moving the peeling wire at a speed of 10 mm/min or more corresponds to peeling the pressure-sensitive adhesive sheet at a tensile speed of 20 mm/min or more under conditions of, for example, a peeling angle of 180 degrees. The speed at which the peeling wire is moved may be, for example, 50 mm/min or more, 150 mm/min or more, 300 mm/min or more, or 500 mm/min or more. According to the peeling method disclosed herein, by peeling the adhesive sheet from the adherend while advancing the entry of the aqueous liquid into the interface, good water peelability can be exhibited even at such a relatively high peeling speed. The upper limit of the speed at which the peeling wire is moved is not particularly limited. The speed of moving the peeling wire may be, for example, 1000 mm/min or less.

In the peeling method disclosed herein, for example, the peeling area of the pressure-sensitive adhesive sheet per 10 μL of the volume of the aqueous liquid (for example, water) used in the method is, for example, 50 cm 2 or more, preferably 100 cm 2 or more. It can be carried out in the form of becoming.

The peeling method disclosed herein can be preferably applied to peeling of a pressure-sensitive adhesive sheet affixed to a non-absorbent smooth surface such as, for example, a glass plate, a metal plate, or a resin plate. Moreover, the peeling method disclosed here can be used suitably as a method of peeling an adhesive sheet from any optical member mentioned above. Especially, it is preferable as a method of peeling the adhesive sheet affixed to a glass plate, such as an alkali glass and an alkali-free glass.

In addition, the following are included in matters disclosed by this specification.

(1) As an adhesive sheet having an adhesive layer,

The pressure-sensitive adhesive layer includes a layer A constituting at least one surface of the pressure-sensitive adhesive layer,

The adhesive strength (N0) after 1 day at room temperature after affixing the layer A side to the adherend is 2.0 N/10 mm or more,

The water-resistant adhesive strength (N1) [N/10 mm] measured after attaching the layer A side to the adherend, and after 1 day at room temperature, immersed in water for 30 minutes, and then pulled up from water to wipe off the adherent water, and the adhesive force ( From N0) [N/10 mm], the following formula: (1-(N1/N0)) × 100; The water-resistant adhesive strength reduction rate calculated by is 30% or less, and

After affixing the layer A side of the pressure-sensitive adhesive sheet to the adherend, and after 1 day at room temperature, a drop of water is added dropwise to the adherend, and the water enters one end of the interface between the pressure-sensitive adhesive layer and the adherend, and then a new From the water peeling force (N2) [N/10 mm] measured by peeling without supplying water, and the adhesive force (N0) [N/10 mm], the following equation: (1-(N2/N0)) × 100; The pressure-sensitive adhesive sheet in which the water peeling adhesion reduction rate calculated by is 40% or more.

(2) The adhesive sheet according to (1), wherein the layer A contains a water affinity agent.

(3) The adhesive sheet according to (2), wherein the content of the water affinity agent is 0.2 parts by weight or more and 20 parts by weight or less based on 100 parts by weight of the monomer component constituting the polymer contained in the layer A.

(4) The adhesive sheet according to any one of (1) to (3), wherein the layer A is water-insoluble and non-water swellable.

(5) The layer A is composed of an acrylic pressure-sensitive adhesive containing an acrylic polymer,

The pressure-sensitive adhesive sheet according to any one of (1) to (4) above, wherein 50% by weight or more of the monomer component constituting the acrylic polymer is an alkyl (meth)acrylate having an alkyl group having 1 to 20 carbon atoms at the ester terminal. .

(6) The pressure-sensitive adhesive sheet according to any one of (1) to (5), wherein the thickness of the pressure-sensitive adhesive layer is 10 μm or more and 200 μm or less.

(7) The pressure-sensitive adhesive sheet according to any one of (1) to (6), wherein the pressure-sensitive adhesive layer further includes a layer B disposed on the back side of the layer A.

(8) The pressure-sensitive adhesive sheet according to (7), wherein the layer B is disposed in direct contact with the back surface of the layer A.

(9) The adhesive sheet according to (7) or (8), wherein the thickness of the layer B is 20 µm or more.

(10) The pressure-sensitive adhesive sheet according to any one of (7) to (9), wherein the thickness of the layer A is 5 µm or more and 50 µm or less.

(11) The layer A is a layer formed from a water-dispersible pressure-sensitive adhesive composition,

The adhesive sheet according to any one of (7) to (10), wherein the layer B is a layer formed from a photocurable adhesive composition or a solvent-type adhesive composition.

(12) As an adhesive sheet having an adhesive layer,

The pressure-sensitive adhesive layer includes a layer A constituting at least one surface of the pressure-sensitive adhesive layer, and a layer B disposed on the back side of the layer A,

The layer A is a layer formed from an aqueous dispersion type pressure-sensitive adhesive composition,

The layer B is a layer formed from a photo-curable pressure-sensitive adhesive composition or a solvent-type pressure-sensitive adhesive composition.

(13) As an adhesive sheet having an adhesive layer,

The pressure-sensitive adhesive layer includes a layer A constituting at least one surface of the pressure-sensitive adhesive layer, and a layer B disposed on the back side of the layer A,

The A layer contains a water affinity, the pressure-sensitive adhesive sheet.

(14) The pressure-sensitive adhesive sheet according to (13), wherein the content of the water affinity agent is 0.2 parts by weight or more and 20 parts by weight or less based on 100 parts by weight of the monomer component constituting the polymer contained in the layer A.

(15) The adhesive sheet according to any one of (12) to (14), wherein the layer A is water-insoluble and non-water-swellable.

(16) The water-resistant adhesive strength (N1) [N/10 mm] measured after attaching the layer A side to the adherend, and after 1 day at room temperature, immersed in water for 30 minutes, and then pulled up from water to wipe off the adherent water, and From the adhesive force (N0) [N/10 mm], the following formula: (1-(N1/N0)) × 100; The water-resistant adhesive strength reduction rate calculated by is 30% or less, and

After affixing the layer A side of the pressure-sensitive adhesive sheet to the adherend, and after 1 day at room temperature, a drop of water is added dropwise to the adherend, and the water enters one end of the interface between the pressure-sensitive adhesive layer and the adherend, and then a new From the water peeling force (N2) [N/10 mm] measured by peeling without supplying water, and the adhesive force (N0) [N/10 mm], the following equation: (1-(N2/N0)) × 100; The pressure-sensitive adhesive sheet according to any one of the above (12) to (15), wherein the water peeling adhesion reduction rate calculated by is 40% or more.

(17) The pressure-sensitive adhesive sheet according to any one of (12) to (16), wherein the A-layer side is affixed to the adherend, and the adhesion (N0) after one day at room temperature is 2.0 N/10 mm or more.

(18) The pressure-sensitive adhesive sheet according to any one of (12) to (17), wherein the layer B is disposed in direct contact with the back surface of the layer A.

(19) The adhesive sheet according to any one of (12) to (18), wherein the thickness of the layer B is 20 µm or more.

(20) The pressure-sensitive adhesive sheet according to any one of (12) to (19), wherein the thickness of the layer A is 5 µm or more and 50 µm or less.

(21) The layer A is composed of an acrylic pressure-sensitive adhesive containing an acrylic polymer,

The pressure-sensitive adhesive sheet according to any one of (12) to (20) above, wherein 50% by weight or more of the monomer component constituting the acrylic polymer is an alkyl (meth)acrylate having an alkyl group having 1 to 20 carbon atoms at the ester terminal. .

(22) The pressure-sensitive adhesive sheet according to any one of (12) to (21), wherein the thickness of the pressure-sensitive adhesive layer is 10 μm or more and 200 μm or less.

(23) A member with an adhesive sheet comprising the adhesive sheet according to any one of the above (1) to (22) and a member bonded to the one surface of the adhesive layer.

(24) The adhesive sheet attachment member according to (23), wherein the member has a contact angle of 50 degrees or less with respect to distilled water on a surface in contact with the adhesive layer.

(25) As a peeling method of the pressure-sensitive adhesive sheet affixed to an adherend,

In a state in which an aqueous liquid exists at the interface between the adherend and the adhesive sheet in the peeling wire of the adhesive sheet from the adherend, the aqueous liquid enters the interface by following the movement of the peeling wire. A peeling method comprising a water peeling step of peeling the adhesive sheet from the adherend while making it.

(26) The peeling method according to (25), wherein the adhesive sheet is the adhesive sheet according to any one of (1) to (22).

(27) The peeling method according to (25) or (26), wherein in the water peeling step, the peeling wire is moved at a speed of 10 mm/min or more.

(28) The adhesive sheet attachment member according to any one of (25) to (27), wherein the adherend has a contact angle of 50 degrees or less with respect to distilled water on a surface in contact with the adhesive layer.

(29) The step of peeling the adhesive sheet from the member to be adhered by the peeling method according to any one of (25) to (28), and

A method for producing a member with an adhesive sheet, comprising a step of affixing an adhesive sheet separate from the peeled adhesive sheet to the member from which the adhesive sheet has been peeled off.

Example

Hereinafter, some examples of the present invention will be described, but it is not intended to limit the present invention to those shown in these examples. In addition, in the following description, "part" and "%" are based on weight unless otherwise noted.

≪Experimental Example 1≫

<Preparation of adhesive composition>

(Adhesive composition U-1)

2-ethylhexyl acrylate (2EHA), N-vinyl-2-pyrrolidone (NVP), 2-hydroxyethyl acrylate (HEA) and isobornyl acrylate (IBXA) by 80/35/5/30 A four-neck flask with 100 parts of the monomer mixture contained in a weight ratio of, as a photoinitiator, as a photoinitiator: 0.05 parts of Irgacure 651 (manufactured by Chiba Specialty Chemicals) and 0.05 parts of brand name: Irgacure 184 (manufactured by Chiba Specialty Chemicals) And photopolymerization by irradiation with ultraviolet rays until the viscosity (BH viscometer, No.5 rotor, 10 rpm, measurement temperature 30° C.) becomes about 15 Pa·s in a nitrogen atmosphere, thereby forming a partial polymer of the monomer mixture. A monomer syrup containing was prepared.

To 100 parts of this monomer syrup, 0.13 parts of 1,6-hexanediol diacrylate (HDDA) and 0.33 parts of a photopolymerization initiator (trade name: Irgacure 651, manufactured by Chiba Specialty Chemicals) were added, uniformly mixed, and ultraviolet rays Curable pressure-sensitive adhesive composition U-1 was prepared.

(Adhesive composition U-2)

n-butyl acrylate (BA), cyclohexyl acrylate (CHA), NVP, 4-hydroxybutyl acrylate (4HBA) and isostearyl acrylate (ISTA) in a weight ratio of 70/10/10.5/15/21.1 100 parts of the monomer mixture contained as a photoinitiator as a photoinitiator: 0.05 parts of Irgacure 651 (manufactured by Chiba Specialty Chemicals) and 0.05 parts of brand name: Irgacure 184 (manufactured by Chiba Specialty Chemicals) were added to a four-neck flask together And photopolymerization by irradiation with ultraviolet rays until the viscosity (BH viscometer, No.5 rotor, 10 rpm, measurement temperature 30° C.) is about 15 Pa·s in a nitrogen atmosphere, thereby containing partial polymers of the monomer mixture. A monomer syrup was prepared.

To 100 parts of this monomer syrup, 0.4 parts of HDDA, 0.4 parts of a photoinitiator (trade name: Irgacure 651, manufactured by Chiba Specialty Chemicals), and α-methylstyrene dimer as a chain transfer agent ("Nofuma MSD" manufactured by Nichiyu) 0.08 part was added, it mixed uniformly, and the ultraviolet-curable adhesive composition U-2 was prepared.

(Adhesive composition S-1)

To a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirring device, 98 parts of BA, 1 part of HEA, and 1 part of acrylic acid (AA) were added to 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator. ) A solution containing an acrylic polymer having Mw of 1.8 million (solid content concentration 30%) was obtained by adding 0.3 parts and ethyl acetate as a polymerization solvent and reacting at 60° C. for 4 hours under a nitrogen gas stream. Per 100 parts of the solid content of this acrylic polymer solution, 0.3 parts of dibenzoyl peroxide (manufactured by Nippon Oil, Nippa BO-Y), and 0.02 parts of trimethylolpropane/tolylene diisocyanate terpolymer adduct (manufactured by Tosoh, Colonate L) and , 0.1 part of a silane coupling agent (3-glycidoxypropyltrimethoxysilane) was blended, stirred and mixed uniformly, to prepare a solvent-type pressure-sensitive adhesive composition S-1.

(Adhesive composition S-2)

In a reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer and a stirring device, 95 parts of BA, 50 parts of 2EHA and 5 parts of AA as a monomer component, 0.2 parts of AIBN as a thermal polymerization initiator, and 233 parts of ethyl acetate as a polymerization solvent were added. The solution was injected and reacted at 60° C. for 8 hours in a nitrogen gas stream to obtain a solution containing an acrylic polymer having a Mw of 700,000. Per 100 parts of the solid content of this acrylic polymer solution, 25 parts of rosin ester resin (manufactured by Arakawa Chemical Industries, Pencel D-125) as tackifying resin, trimethylolpropane/tolylenediisocyanate trimer adduct (manufactured by Tosoh Corporation, brand name `` Colonate L") 2 parts were added, it stirred and mixed uniformly, and the solvent-type adhesive composition S-2 was prepared.

(Adhesive composition E-1)

2EHA 85 parts, MA 13 parts, AA 1.2 parts, MAA 0.8 parts, 3-methacryloxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd., KBM-503) 0.02 parts, t-dodecylmercaptan 0.048 parts as a chain transfer agent And 2.0 parts of an emulsifier (made by Kao Corporation, Latte product E-118B) were mixed and emulsified in 100 parts of ion-exchanged water to prepare an aqueous emulsion (monomer emulsion) of a monomer mixture.

The monomer emulsion was put into a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirring device, and stirred at room temperature for 1 hour or more while introducing nitrogen gas. Then, the system was heated to 60° C., and 0.1 part of 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate (manufactured by Wako Pure Chemical Industries, Ltd., VA-057) was added as a polymerization initiator. It was added and reacted at 60° C. for 6 hours to obtain an aqueous dispersion of an acrylic polymer. After cooling the system to room temperature, by adjusting the pH to about 7.5 and the viscosity to about 9 Pa·s using 10% aqueous ammonia as a pH adjuster and polyacrylic acid (a 36% nonvolatile aqueous solution) as a thickener, emulsion-type pressure-sensitive adhesive composition E- 1 was prepared.

(Adhesive composition E-2)

Per 100 parts of the solid content of the aqueous dispersion of the acrylic polymer obtained in the preparation of the pressure-sensitive adhesive composition E-1, a tackifying resin emulsion (manufactured by Arakawa Chemicals, Superester E-865NT, an aqueous dispersion of a polymerized rosin ester having a softening point of 160°C) is 30 to the solid content. Was added. In addition, by using 10% aqueous ammonia as a pH adjuster and polyacrylic acid (a 36% nonvolatile aqueous solution) as a thickener, adjusting the pH to about 7.5 and the viscosity to about 9 Pa·s to prepare an emulsion-type pressure-sensitive adhesive composition E-2. I did.

<Production of adhesive sheet (1)>

(Example 1)

A pressure-sensitive adhesive composition U-1 was applied to a 38 µm-thick release film R1 (Mitsubishi Resin Co., Ltd., MRF#38) in which one side of the polyester film is the release side, and the thickness 38 that one side of the polyester film is the release side. A µm release film R2 (Mitsubishi Resin Co., Ltd., MRE#38) was covered to block air, irradiated with ultraviolet rays, and cured to form a 130 µm-thick pressure-sensitive adhesive layer B1. Subsequently, the release film R2 covering the pressure-sensitive adhesive layer B1 is peeled off, and the PET film (support), the pressure-sensitive adhesive layer B1 and the release film R1 are laminated in this order by bonding the corona-treated polyethylene terephthalate (PET) film with a thickness of 75 μm. Obtained a laminated sheet.

The pressure-sensitive adhesive composition E-1 was applied to the release film R1 (Mitsubishi Resin Co., Ltd., MRF#38), and dried at 120° C. for 3 minutes to form a pressure-sensitive adhesive layer A1 having a thickness of 20 μm. By peeling off the release film R1 covering the pressure-sensitive adhesive layer B1 of the laminated sheet, and bonding the pressure-sensitive adhesive layer A1 thereto, the pressure-sensitive adhesive layer B1 and the pressure-sensitive adhesive layer A1 directly contact each other to include a two-layered pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer A pressure-sensitive adhesive sheet having a structure in which a PET film (support) was bonded to the surface of the B1 layer side was obtained. The surface on the side of the A1 layer of this PSA sheet is protected by the release film R1 used for formation of the PSA layer A1.

(Example 2)

Except having used the adhesive composition E-2 instead of the adhesive composition E-1, it carried out similarly to Example 1, and produced the adhesive sheet concerning this example.

(Example 3)

The pressure-sensitive adhesive composition S-2 was applied to the release film R1 (Mitsubishi Resin Co., Ltd., MRF#38), and dried at 130° C. for 5 minutes to form a 50-µm-thick pressure-sensitive adhesive layer B3. A laminated sheet in which the PET film (support), the pressure-sensitive adhesive layer B3 and the release film R1 were laminated in this order was obtained by bonding a corona-treated PET film with a thickness of 75 µm to this pressure-sensitive adhesive layer B3.

The release film R1 covering the pressure-sensitive adhesive layer B3 of the laminated sheet was peeled off, and the pressure-sensitive adhesive layer A1 having a thickness of 20 µm formed on the release surface of the release film R1 was bonded in the same manner as in Example 1, whereby the pressure-sensitive adhesive layer B3 and the pressure-sensitive adhesive layer A1 A pressure-sensitive adhesive sheet having a structure in which a two-layered pressure-sensitive adhesive layer was directly contacted and laminated was included, and a PET film (support) was bonded to the surface on the B3 layer side of the pressure-sensitive adhesive layer was obtained.

(Example 4)

Except having used the adhesive composition S-1 instead of the adhesive composition E-1, it carried out similarly to Example 1, and produced the adhesive sheet which concerns on this example.

(Example 5)

The pressure-sensitive adhesive composition U-1 was applied to the release film R1 (Mitsubishi Resin Co., Ltd., MRF#38), and the release film R2 (Mitsubishi Resin Co., Ltd., MRE#38) was covered to block air and irradiated with ultraviolet rays to cure it. A µm pressure-sensitive adhesive layer B5 was formed. Subsequently, the release film R2 covering the pressure-sensitive adhesive layer B5 was peeled off, and a 75 μm-thick polyethylene terephthalate (PET) film subjected to corona treatment was bonded to each other, whereby the PET film (support), the pressure-sensitive adhesive layer, and the release film R1 were laminated in this order. A laminated sheet was obtained.

(Example 6)

The pressure-sensitive adhesive composition S-2 was applied to the release film R1 (Mitsubishi Resin Co., Ltd., MRF#38), and dried at 130° C. for 5 minutes to form a 50-µm-thick pressure-sensitive adhesive layer B3. The pressure-sensitive adhesive composition S-2 was applied to the release film R2 (Mitsubishi Resin Co., Ltd., MRE#38), and dried at 130° C. for 5 minutes to form a pressure-sensitive adhesive layer B6 having a thickness of 50 μm. By bonding a nonwoven fabric (Daifuku Paper Co., Ltd., SP-14K) to the pressure-sensitive adhesive layer B3 on the release film R1, and bonding the pressure-sensitive adhesive layer B6 on the release film R2 to the opposite surface of the nonwoven fabric, the pressure-sensitive adhesive layer B3 and the pressure-sensitive adhesive layer B6 serve as intermediate layers. A double-sided pressure-sensitive adhesive sheet having a laminated configuration was produced through a nonwoven fabric.

The release film R2 covering the pressure-sensitive adhesive layer B6 of the double-sided pressure-sensitive adhesive sheet is peeled off, and a corona-treated PET film having a thickness of 75 μm is bonded to the pressure-sensitive adhesive layer B6, thereby making a PET film (support), an adhesive layer B6, a nonwoven fabric, and an adhesive layer. B3 and release film R1 were laminated in this order to obtain a laminated sheet.

(Example 7)

In a 1 liter three-necked flask, 45 parts of caprolactone acrylate (Toa Synthesis, Aronix M-5300), 50 parts of BA, 5 parts of sodium styrene sulfonate, 8.8 parts of potassium hydroxide, 96 parts of water, 144 parts of methanol, AIBN 0.175 Part was added, mixed, and reacted at 60° C. for 5 hours under a nitrogen gas stream to obtain an acrylic polymer solution. In this solution, with respect to 100 parts of the acrylic polymer, 20 parts of a water-soluble plasticizer (trade name "Sanix SP750" manufactured by Sanyo Chemical Co., Ltd., and a diglycidyl ether of polyethylene glycol having a polymerization degree of about 9 as a crosslinking agent (Nagase Chemical, EX- 830) 0.2 part was blended, and it mixed uniformly, and the adhesive composition P-1 was prepared.

Except having formed the water-swellable adhesive layer by using the adhesive composition P-1 in place of the adhesive composition E-1, it carried out similarly to Example 1, and produced the adhesive sheet concerning this example.

(Example 8)

In the same manner as in Example 1, a laminated sheet in which a PET film (support), an adhesive layer B1, and a release film R1 were laminated in this order was obtained. The peeling film R1 covering the pressure-sensitive adhesive layer B1 of this laminated sheet was peeled off, and a commercially available water-soluble double-sided pressure-sensitive adhesive tape (manufactured by Clover Co., Ltd.) was bonded thereto to prepare the pressure-sensitive adhesive sheet according to this example.

<Performance evaluation (1)>

With respect to the pressure-sensitive adhesive sheets obtained in Examples 1 to 8, the state adhesive force (N0), water-resistant adhesive force (N1), and water peeling force (N2) on the layer A side were measured by the method described above. As the adherend, an alkali glass plate (manufactured by Matsunami Glass Industry Co., Ltd., produced by the float method, thickness 1.35 mm, a blue plate polishing product, and a contact angle with respect to distilled water on the surface to which the adhesive sheet is bonded: 8 degrees) was used. From the obtained results, the water-resistant adhesive strength reduction rate and the water peeling adhesive strength reduction ratio were calculated. Table 1 shows the results.

As shown in Table 1, the pressure-sensitive adhesive sheet according to Examples 1 to 5 has a low water-resistance reduction rate and a high water-removal adhesion reduction rate, so that it can be easily peeled from an adherend using a small amount of water, and The reliability was also excellent. In Examples 1 to 3, particularly favorable results were obtained. On the other hand, the pressure-sensitive adhesive sheet according to Example 6 was difficult to peel with water. In addition, the pressure-sensitive adhesive sheets according to Examples 7 and 8 had low water resistance reliability. More specifically, in the pressure-sensitive adhesive sheet according to Example 7, the entire test piece naturally peeled off from the adherend and floated in the middle of water immersion for 30 minutes, pulled up from water, and the peel strength could not be measured. Therefore, in Table 1, the water-resistant adhesive force N1 of Example 7 is indicated as 0 N/10 mm for convenience. Also in the pressure-sensitive adhesive sheet according to Example 8, lifting from the adherend occurred from the tip to a part of the test piece by the water immersion for 30 minutes. In addition, on the adherend surface after the pressure-sensitive adhesive sheet according to Example 7 was naturally peeled off by water immersion, and on the adherend surface after measurement of the water-resistant adhesive force (N1) of the pressure-sensitive adhesive sheet according to Example 8, residue of glue was observed. On the other hand, in the pressure-sensitive adhesive sheets according to Examples 1 to 6, no glue residue was observed on the adherend surface after peeling of the test piece in either of the measurement of the water-resistant adhesive force (N1) and the measurement of the water peeling force (N2). In addition, although specific numerical values are not shown, each of the pressure-sensitive adhesive layers formed from the pressure-sensitive adhesive compositions U-1, U-2, S-1, S-2, E-1, and E-2 is both water-insoluble and non-water swellable. Has been confirmed.

≪Experimental Example 2≫

<Preparation of adhesive composition (2)>

(Adhesive composition B-1)

In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirring device, as a monomer component, BA 64.5 parts, CHA 6 parts, NVP 9.6 parts, ISTA 5 parts and 4HBA 14.9 parts, and α-thioglycerol 0.07 as a chain transfer agent. Part, 122 parts of ethyl acetate were injected as a polymerization solvent, 0.2 parts of AIBN was added as a thermal polymerization initiator, and solution polymerization was carried out in a nitrogen atmosphere to obtain a solution containing an acrylic polymer having an Mw of 600,000.

To the acrylic polymer solution obtained above, per 100 parts of the monomer component used to prepare the solution, an isocyanate crosslinking agent (trimethylolpropane/xylylenediisocyanate adduct (manufactured by Mitsui Chemicals Co., Ltd., Takenate D-110N, solid content concentration 75% by mass) ) 0.09 parts based on solid content, 0.4 parts of acrylic oligomer, 0.02 parts of dioctyltin dilaurate (manufactured by Tokyo Fine Chemicals, Enviraiza OL-1) as a crosslinking accelerator, 3 parts of acetylacetone as a crosslinking retardant, polyfunctional monomer 2.7 parts of dipentaerythritol hexaacrylate (DPHA) as a photopolymerization initiator, 0.22 parts of Irgacure 184 (manufactured by Chiba Specialty Chemicals Co., Ltd.) were added as a photopolymerization initiator, and the mixture was uniformly mixed to prepare a pressure-sensitive adhesive composition B-1.

As the acrylic oligomer, one synthesized by the following method was used.

[Synthesis of acrylic oligomer]

Toluene 100 parts, dicyclopentanyl methacrylate (DCPMA) (trade name: FA-513M, manufactured by Hitachi Chemical Industries, Ltd.) 60 parts, methyl methacrylate (MMA) 40 parts, and α-thioglycerol 3.5 parts as a chain transfer agent 4 Into the old flask. And after stirring at 70 degreeC in nitrogen atmosphere for 1 hour, 0.2 part of AIBN was put as a thermal polymerization initiator, it was made to react at 70 degreeC for 2 hours, and it was made to react at 80 degreeC for 2 hours. Thereafter, the reaction solution was put in a temperature atmosphere of 130°C, and toluene, a chain transfer agent, and an unreacted monomer were dried and removed to obtain a solid acrylic oligomer. Tg of this acrylic oligomer was 144°C, and Mw was 4300.

<Production of adhesive sheet (2)>

(Example 9)

The pressure-sensitive adhesive composition B-1 was applied to a 38 µm-thick release film R1 (Mitsubishi Resin Co., Ltd., MRF#38) in which one side of the polyester film is a release surface, and dried at 135°C for 2 minutes, and a thickness of 130 µm, A pressure-sensitive adhesive layer B9 having photocrosslinking property was formed. A laminated sheet in which a PET film (support), a pressure-sensitive adhesive layer B9, and a release film R1 were laminated in this order was obtained by bonding a corona-treated polyethylene terephthalate (PET) film with a thickness of 75 μm to this pressure-sensitive adhesive layer B9.

The pressure-sensitive adhesive composition E-1 was applied to the release film R1 (Mitsubishi Resin Co., Ltd., MRF#38), and dried at 120° C. for 3 minutes to form a pressure-sensitive adhesive layer A1 having a thickness of 20 μm. By peeling the release film R1 covering the pressure-sensitive adhesive layer B9 of the laminated sheet, and bonding the pressure-sensitive adhesive layer A1 thereto, the two-layered adhesive layer B9 and the pressure-sensitive adhesive layer A1 directly contact each other in this order on the PET film (support). A pressure-sensitive adhesive layer of the structure was formed. The surface on the side of the A1 layer of this PSA sheet is protected by the release film R1 used for formation of the PSA layer A1.

<Performance evaluation (2)>

About the adhesive sheet obtained by Example 9, the state adhesive force (N0), water resistance adhesive force (N1), and water peeling force (N2) on the A layer side were measured. Each measurement was carried out by placing an adhesive sheet on an alkali glass plate (manufactured by Matsunami Glass Industries, Ltd., produced by the float method, thickness 1.35 mm, a blue plate polishing product, and the contact angle of the surface to which the adhesive sheet is bonded to distilled water: 8 degrees) as an adherend. After sticking with and performing light irradiation through the said alkali glass plate in an environment of 23 degreeC and 50% RH, it implemented by the said method. The light irradiation was performed by irradiating ultraviolet rays with a cumulative amount of light of 3000 mJ/cm 2 using a high-pressure mercury lamp (300 mJ/cm 2 ). From the obtained results, the water-resistant adhesive strength reduction rate and the water peeling adhesive strength reduction ratio were calculated. The results are shown in Table 2. In addition, in any measurement of the adhesive force (N0, N1, N2), no glue residue was observed on the adherend surface after peeling of the test piece. In addition, although a specific numerical value is not shown, it is confirmed that the pressure-sensitive adhesive layer B9 after light irradiation is water-insoluble and non-water-swellable.

<Production and evaluation of the adhesive sheet attachment member>

(Example 10)

A commercially available acrylic plate (manufactured by Mitsubishi Chemical Co., Ltd., brand name "acrylic plate (part number 001)", thickness 2 mm × width 200 mm × length 300 mm) was not specifically subjected to hydrophilization treatment on the surface, and in this example It was used as a member (adherence) of. After measuring the contact angle of the surface (bonding surface) of this acrylic plate with distilled water, within 30 minutes from the measurement of the contact angle, the A layer side of the pressure-sensitive adhesive sheet according to Example 9 was affixed to the surface, and the pressure-sensitive adhesive sheet according to this example The attachment member was produced. For this adhesive sheet attachment member, in the same manner as in the measurement of the above-described state adhesive force (N0), water resistant adhesive force (N1), and water peeling force (N2), except that the acrylic plate was used instead of the alkali glass plate, in Example 9 The state adhesive force, water resistance adhesive force, and water peel force of the related pressure-sensitive adhesive sheet to the adherend were measured, and the water-resistant adhesive force decrease rate and the water peel adhesive force decrease rate were calculated. The results are shown in Table 2.

(Examples 11 to 16)

Plasma treatment was performed on the bonding surface of the same acrylic plate used in Example 10 using an atmospheric pressure plasma surface treatment apparatus (manufactured by Sekisui Chemical Industries, AP-T05). In the plasma treatment conditions, the distance from the plasma outlet to the surface of the acrylic plate was 4 mm, the nitrogen flow rate was 60 L/min, the pulse width was 5 μs, the voltage was fixed at 150 V, and the conveying speed of the acrylic plate was 0.2 By changing the frequency in the range of -0.3 m/min, the frequency in the range of 10 Hz-20 kHz, the acrylic plate which has the bonding surface treated with the plasma treatment energy [Ws/cm<2>] shown in Table 2 was obtained. After plasma treatment, the contact angle of the bonding surface of each acrylic plate was measured within 30 minutes. Within 30 minutes from the measurement of the contact angle, the A layer side of the pressure-sensitive adhesive sheet according to Example 9 was affixed to the bonding surface of each acrylic plate to prepare a member with a pressure-sensitive adhesive sheet according to Examples 11 to 16. For these adhesive sheet attachment members, in the same manner as the adhesive sheet attachment member of Example 10, the state adhesive force, water adhesive force, and water peel force of the adhesive sheet according to Example 9 were measured, and the water adhesive strength reduction rate and the water peel adhesive force reduction rate were calculated. . The results are shown in Table 2.

(Example 17)

A PET film having a thickness of 75 µm (manufactured by Toray Corporation, Lumira S10, 75 µm in thickness) was used as a member (adherent) in this example without performing a hydrophilic treatment on the surface in particular. After measuring the contact angle of the surface (bonding surface) of this PET film with distilled water, within 30 minutes from the measurement of the contact angle, the A layer side of the pressure-sensitive adhesive sheet according to Example 9 was affixed to the surface, and the pressure-sensitive adhesive sheet according to this example The attachment member was produced. For convenience of operation, the PET film is a double-sided adhesive tape (manufactured by Nitto Electric Co., Ltd., brand name "No.5000") on the surface of an alkali glass plate (produced by the float method, thickness 1.35 mm, blue plate polishing product) manufactured by Matsunami Glass Industry Co., Ltd. It was fixed to and used. With respect to this adhesive sheet attachment member, in the same manner as in the measurement of the above-described state adhesive force (N0), water resistance adhesive force (N1) and water peeling force (N2), except that the PET film was used instead of the alkali glass plate, in Example 9 The state adhesive force, water resistance adhesive force, and water peel force of the related pressure-sensitive adhesive sheet to the adherend were measured, and the water-resistant adhesive force decrease rate and the water peel adhesive force decrease rate were calculated. The results are shown in Table 2.

(Examples 18 to 19)

On the bonding surface of the same PET film as used in Example 17, a hydrophilic coating agent was applied using a wire bar #5 (manufactured by rds), and then dried at 120°C for 2 minutes to obtain a hydrophilic coating layer having a thickness of 0.2 µm to 0.5 µm. Formed. As the hydrophilic coating agent, in Example 18, the brand name ``Colcoat PC-301'' (indicated by ``PC-301'' in Table 2), and in Example 19, the brand name ``Colcoat N-103X'' manufactured by the company ( In Table 2, "N-103X") was used. The PET film having a hydrophilic surface thus obtained was used as a member (adherent) in Examples 18 and 19. About other points, it carried out similarly to Example 17, and produced the adhesive sheet attachment member concerning Examples 18 and 19. With respect to these adhesive sheet attachment members, in the same manner as the adhesive sheet attachment member of Example 17, the state adhesive force, water adhesive force, and water peel force of the adhesive sheet according to Example 9 were measured, and the water adhesive force reduction rate and the water peel adhesive force decrease rate were calculated. . The results are shown in Table 2.

(Example 20)

An alkali glass plate manufactured by the float method (manufactured by Matsunami Glass Industries, Ltd., thickness 1.35 mm, a blue plate polishing product, and a contact angle of the surface to distilled water: 8 degrees) was prepared. Plasma treatment was performed on the surface of this alkali glass plate with plasma treatment energy [Ws/cm 2] shown in Table 2 by an atmospheric pressure plasma surface treatment apparatus (manufactured by Sekisui Chemical Industries, AP-T05). After measuring the contact angle of the plasma-treated surface (bonding surface) with distilled water, within 30 minutes from the measurement of the contact angle, the A layer side of the pressure-sensitive adhesive sheet according to Example 9 was affixed to the surface, and the pressure-sensitive adhesive sheet according to this example The attachment member was produced. For this adhesive sheet attachment member, in the same manner as in the measurement of the above-described state adhesive force (N0), water resistance adhesive force (N1) and water peeling force (N2), except that the alkali glass plate after plasma treatment was used instead of the untreated alkali glass plate. Then, the state adhesive force, water adhesive force, and water peel force of the pressure-sensitive adhesive sheet according to Example 9 to the adherend were measured, and the water-resistant adhesive force decrease rate and the water peel adhesive force decrease rate were calculated. The results are shown in Table 2.

As shown in Table 2, the pressure-sensitive adhesive sheet according to Example 9 exhibited good water-removability and water-resistance reliability by having a low water-repellent adhesive strength reduction ratio and a high water-repellent adhesive power reduction ratio. In addition, from the results shown in Table 2, in the adhesive sheet attachment member of Examples 10 to 20 produced using the adhesive sheet of Example 9, when the contact angle of the surface in contact with the adhesive layer of the member (adherent) decreases, the adhesive sheet It can be seen that the water peeling property of is generally improved.

≪Experimental Example 3≫

<Preparation of adhesive composition (3)>

(Adhesive composition B-2)

To the acrylic polymer solution obtained from the pressure-sensitive adhesive composition B-1, per 100 parts of the monomer component used to prepare the solution, 3-glycidoxypropyltrimethoxysilane as a silane coupling agent (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.33 Parts, nonionic surfactant A (polyoxyethylene sorbitan monolaurate, HLB 13.3, brand name: Leodol TW-L106, manufactured by Kao) 0.1 parts, isocyanate crosslinking agent (trimethylolpropane/xylylenedi) as a water affinity agent An isocyanate adduct (manufactured by Mitsui Chemical Co., Ltd., Takenate D-110N, solid content concentration 75% by mass) based on solid content 0.09 parts, acrylic oligomer 0.4 parts, dioctyl tin dilaurate as a crosslinking accelerator (manufactured by Tokyo Fine Chemical, Envy Liza OL-1) 0.02 parts, 3 parts of acetylacetone as a crosslinking retarder, 2.7 parts of DPHA as a polyfunctional monomer, 0.22 parts of Irgacure 184 (manufactured by Chiba Specialty Chemicals) as a photoinitiator were added, and mixed uniformly, A solvent-type adhesive composition B-2 was prepared.

(Adhesive composition B-3)

As the water affinity agent, in the same manner as in the pressure-sensitive adhesive composition B-2, except that 0.1 part of an anionic surfactant (sodium lauryl sulfate, brand name: Emar 10G, manufactured by Kao Corporation) was used instead of 0.1 part of the nonionic surfactant A, the pressure-sensitive adhesive composition B-3 was prepared.

(Adhesive composition B-4)

As a water affinity agent, except for using 0.05 parts of nonionic surfactant F (polyoxyethylene lauryl ether, HLB 12.1, brand name: Emargen 108, manufactured by Kao Corporation) instead of 0.1 part of nonionic surfactant A, adhesive composition B- It carried out similarly to 2, and prepared the adhesive composition B-4.

(Adhesive composition B-5)

Except having not used the nonionic surfactant A, it carried out similarly to the adhesive composition B-2, and prepared the adhesive composition B-5.

(Adhesive composition B-6)

To the pressure-sensitive adhesive composition U-1, per 100 parts of the monomer syrup used in the preparation of the composition, as a water affinity nonionic surfactant G (polyoxyethylene sorbitan monolaurate, HLB 16.7, brand name: Leodol TW-L120, Kao Corporation Production) 0.15 part was further added, and it mixed uniformly, and the ultraviolet-curable adhesive composition B-6 was prepared.

(Adhesive composition B-7)

As the water affinity agent, a pressure-sensitive adhesive composition B-7 was prepared in the same manner as in the pressure-sensitive adhesive composition B-6, except that 0.25 parts of PEG400 (polyethylene glycol, average molecular weight 360 to 440) was used instead of 0.15 parts of the nonionic surfactant G.

(Adhesive composition B-8)

Except having not used the nonionic surfactant G, it carried out similarly to the adhesive composition B-6, and prepared the adhesive composition B-8.

<Production of adhesive sheet (3)>

(Example 21)

The pressure-sensitive adhesive composition B-2 obtained above was applied to a 38 µm-thick release film R1 (manufactured by Mitsubishi Resin Co., Ltd., MRF#38) in which one side of the polyester film is a release surface, and dried at 135°C for 2 minutes, A pressure-sensitive adhesive layer having a thickness of 50 µm and having photocrosslinking property was formed. By attaching a 50 µm-thick PET film subjected to corona treatment to this pressure-sensitive adhesive layer, a pressure-sensitive adhesive sheet with a support having a pressure-sensitive adhesive layer on the PET film (support) was obtained. The adhesion surface of this pressure-sensitive adhesive sheet to the adherend (the surface of the adhesive layer on the side opposite to the side attached to the support) is protected by the release film R1.

(Examples 22 to 24)

Except having used each of the adhesive compositions B-3 to B-5 instead of the adhesive composition B-2, it carried out similarly to Example 21, and produced the adhesive sheet concerning each example.

(Example 25)

The pressure-sensitive adhesive composition B-6 obtained above was applied to a 38 µm-thick release film R1 (manufactured by Mitsubishi Resin Co., Ltd., MRF#38) in which one side of the polyester film is the release side, and one side of the polyester film is the release side. A 38 µm-thick release film R2 (manufactured by Mitsubishi Resin Co., Ltd., MRE#38) was covered to block air and irradiated with ultraviolet rays to cure to form a 50 µm-thick, photo-crosslinkable pressure-sensitive adhesive layer. Subsequently, the release film R2 covering the pressure-sensitive adhesive layer was peeled off, and a 50 μm-thick PET film subjected to corona treatment was bonded to each other to obtain a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on the PET film (support). The adhesion surface of this pressure-sensitive adhesive sheet to the adherend is protected by the release film R1.

(Example 26, Example 27)

Except having used each of the adhesive compositions B-7 and B-8 instead of the adhesive composition B-6, it carried out similarly to Example 25, and produced the adhesive sheet concerning each example.

<Performance evaluation (3)>

The state adhesive force (N0), water resistance adhesive force (N1), and water peeling force (N2) of the pressure-sensitive adhesive sheets obtained in Examples 21 to 27 were measured by the method described above. Each measurement was carried out by placing an adhesive sheet on an alkali glass plate (manufactured by Matsunami Glass Industries, Ltd., produced by the float method, thickness 1.35 mm, a blue plate polishing product, and the contact angle of the surface to which the adhesive sheet is bonded to distilled water: 8 degrees) as an adherend. After sticking with and performing light irradiation through the said alkali glass plate in an environment of 23 degreeC and 50% RH, it implemented by the said method. The light irradiation was performed by irradiating ultraviolet rays with a cumulative amount of light of 3000 mJ/cm 2 using a high-pressure mercury lamp (300 mJ/cm 2 ). From the obtained results, the water-resistant adhesive strength reduction rate and the water peeling adhesive strength reduction ratio were calculated. The results are shown in Table 3.

As shown in Table 3, the pressure-sensitive adhesive sheet according to Examples 21 to 27 has a low water-resistance reduction rate and a high water-removal adhesion reduction rate, so that it can be easily peeled from an adherend using a small amount of water, and water resistance reliability It was also excellent. In Examples 21 to 23 and Examples 25 to 26, particularly favorable results were obtained. In addition, although a specific numerical value is not shown, it was confirmed that each of the adhesive layers formed from the adhesive compositions B-2 to 8 is both water-insoluble and non-water-swellable.

≪Experimental Example 4≫

Of the pressure-sensitive adhesive sheets produced in Experimental Examples 1 and 3, a static load peeling test was performed by the above method, and a dry peeling distance and a water entry distance were measured. The results are shown in Table 4. In Example 1, since the peeling proceeded to the end of the test piece within 10 seconds after supplying distilled water and the test piece fell from the adherend, the water peeling distance was described as "more than 100 [mm]". In Table 4, the water-resistant adhesive force reduction rate of each adhesive sheet obtained in Experimental Examples 1 and 3 is also shown.

As shown in Table 4, the pressure-sensitive adhesive sheets according to Examples 1, 2, 21, and 23 exhibit good retention properties before supplying water to the interface because the dry peeling distance is short, and by supplying water to the interface, they can be easily removed from the adherend. It was peelable. These pressure-sensitive adhesive sheets were also excellent in water-resistance reliability because the water-resistant adhesive strength reduction rate was low.

As mentioned above, although the specific example of this invention was demonstrated in detail, these are only an illustration and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

1, 2: adhesive sheet
10: pressure-sensitive adhesive layer (A layer)
10A: One side surface (adhesive surface)
10B: the other surface
20: support
20A: first side
20B: 2nd side (rear)
30: release liner
50: adhesive sheet with release liner
70: absent
80: alkali glass plate (adherent)
80A: Surface with a contact angle of 5 to 10 degrees for distilled water
82: test piece
82A: adhesive side
822: first
84: weight
86: micro syringe
110: adhesive layer
110A: One side surface (adhesive surface)
112: A floor
114: B floor
200: adhesive sheet attachment member

Claims (20)

As an adhesive sheet having an adhesive layer,
The pressure-sensitive adhesive layer includes a layer A constituting at least one surface of the pressure-sensitive adhesive layer,
The adhesive strength (N0) after 1 day at room temperature of the alkali glass plate produced by the float method as an adherend having a contact angle of 5 to 10 degrees to distilled water is at least 2.0 N/10 mm,
The layer A side was affixed to the surface of the alkali glass plate produced by the float method as an adherend having a contact angle of 5 to 10 degrees with distilled water, and 1 day at room temperature, immersed in water for 30 minutes, and then pulled up from water to remove the adhered water. From the water-resistant adhesive force (N1) [N/10 mm] measured after wiping off and the adhesive force (N0) [N/10 mm], the following equation: (1-(N1/N0)) × 100; The water-resistant adhesive strength reduction rate calculated by is 30% or less, and
The layer A side was affixed to the surface of the alkaline glass plate produced by the float method as an adherend with a contact angle of 5 to 10 degrees with respect to distilled water, and after 1 day at room temperature, 20 μL of distilled water was added dropwise to the adherend, and the distilled water was added to the above After entering the one end of the interface between the pressure-sensitive adhesive layer and the adherend, according to JIS Z0237:2009 10.4.1 Method 1: 180° peel adhesion to the test plate, specifically, using a tensile tester at a test temperature of 23°C. From the water peeling force (N2) [N/10 mm] measured under conditions of a tensile speed of 300 mm/min and a peeling angle of 180 degrees, and the adhesive force (N0) [N/10 mm], the following equation: (1-(N2) /N0)) × 100; The water peeling adhesion reduction rate calculated by is 75% or more,
The layer A is a layer formed from a photocurable pressure sensitive adhesive composition or a solvent type pressure sensitive adhesive composition,
The layer A is water-insoluble and non-water swellable,
The layer A is composed of an acrylic pressure-sensitive adhesive containing an acrylic polymer, and 40% by weight or more of the monomer components constituting the acrylic polymer is an alkyl (meth)acrylate having an alkyl group having 4 to 20 carbon atoms at the ester terminal. Ester,
The layer A contains one or two or more water affinity agents selected from the group consisting of surfactants, hydrophilic plasticizers, and water-soluble polymers,
The content of the water affinity agent is 0.01 parts by weight or more and 5 parts by weight or less based on 100 parts by weight of the monomer component constituting the polymer contained in the layer A. As an adhesive sheet having an adhesive layer,
The pressure-sensitive adhesive layer includes a layer A constituting at least one surface of the pressure-sensitive adhesive layer,
The layer A side was affixed to the surface of the alkali glass plate produced by the float method as an adherend having a contact angle of 5 to 10 degrees with distilled water, and 1 day at room temperature, immersed in water for 30 minutes, and then pulled up from water to remove the adhered water. From the water resistance (N1) [N/10 mm] measured after wiping off, and the adhesion (N0) [N/10 mm] after 1 day at room temperature after affixing the layer A side to the surface of the alkali glass plate, the following equation: (1-(N1/N0)) x 100; The water-resistant adhesive strength reduction rate calculated by is 30% or less, and
The dry peeling distance measured by the following static load peeling test is 0.5 mm or less, and the water entry distance is 10 mm or more,
The adhesive strength (N0) [N/10 mm] after 1 day at room temperature after attaching the layer A side to the surface of the alkali glass plate produced by the float method as an adherend having a contact angle of 5 to 10 degrees with distilled water and as an adherend The layer A side was affixed to the side of the alkali glass plate produced by the float method having a contact angle of 5 to 10 degrees with distilled water, and after 1 day at room temperature, 20 µl of distilled water was added dropwise to the adherend, and the distilled water was added to the adhesive. After entering the one end of the interface between the layer and the adherend, according to JIS Z0237: 2009 10.4.1 Method 1: 180° peeling adhesion to the test plate, specifically, tensile using a tensile tester at a test temperature of 23°C. From the water peeling force (N2) [N/10 mm] measured under the conditions of a speed of 300 mm/min and a peeling angle of 180 degrees, the following equation: (1-(N2/N0))×100; The water peeling adhesion reduction rate calculated by is 75% or more,
The layer A is a layer formed from a photocurable pressure sensitive adhesive composition or a solvent type pressure sensitive adhesive composition,
The layer A is water-insoluble and non-water swellable,
The layer A is composed of an acrylic pressure-sensitive adhesive containing an acrylic polymer, and 40% by weight or more of the monomer components constituting the acrylic polymer is an alkyl (meth)acrylate having an alkyl group having 4 to 20 carbon atoms at the ester terminal. Ester,
The layer A contains one or two or more water affinity agents selected from the group consisting of surfactants, hydrophilic plasticizers, and water-soluble polymers,
The content of the water affinity agent is 0.01 parts by weight or more and 5 parts by weight or less based on 100 parts by weight of the monomer component constituting the polymer contained in the layer A.
[Static load peeling test]
The pressure-sensitive adhesive sheet to be measured is cut into a rectangle having a width of 10 mm and a length of 150 mm to prepare a test piece. The side of the layer A of the test piece is bonded with a hand roller to a surface of an alkali glass plate produced by the float method as an adherend having a contact angle of 5 to 10 degrees with respect to distilled water to obtain a sample for evaluation. This sample for evaluation is put into an autoclave, and it processes for 15 minutes under the conditions of a pressure of 5 atm and a temperature of 50°C. After holding the sample for evaluation taken out from the autoclave in an environment of 23°C and 50% RH for 1 day, under the same environment, a range of 50 mm from one end in the longitudinal direction of the test piece was peeled off from the adherend to form a free end, and The adherend is fixed horizontally by opening the side on which the test piece is affixed downward. Next, a 100 g weight is fixed to the free end of the test piece, and 1 minute after the weight is fixed, 20 μL of distilled water is supplied to the interface between the test piece and the adherend. The weight is fixed to the free end, and the distance at which the peeling of the test piece has progressed from the adherend of the test piece for 1 minute after 0 seconds is measured, and it is set as the dry peeling distance. Distilled water is supplied to the interface and the distance at which the peeling has progressed from 0 seconds to 10 seconds is measured to be the water entry distance. The method according to claim 1 or 2,
The content of the water affinity agent is 0.01 parts by weight or more and less than 1 part by weight based on 100 parts by weight of the monomer component constituting the polymer contained in the layer A. The method according to claim 1 or 2,
50% by weight or more of the monomer components constituting the acrylic polymer is an alkyl (meth)acrylate having an alkyl group having 1 to 20 carbon atoms at the ester terminal. The method according to claim 1 or 2,
The monomer component constituting the acrylic polymer is the following conditions:
(A) 40% by weight or more of an alkyl (meth)acrylate having an alkyl group having 6 to 18 carbon atoms in the ester terminal; And
(B) 60% by weight or more of an alkyl (meth)acrylate having an alkyl group having 4 to 18 carbon atoms at the ester terminal;
A pressure-sensitive adhesive sheet that satisfies any one of. The method according to claim 1 or 2,
The thickness of the pressure-sensitive adhesive layer is 10 μm or more and 200 μm or less. The method according to claim 1 or 2,
The pressure-sensitive adhesive layer further includes a layer B disposed on the rear side of the layer A. The method of claim 7,
The pressure-sensitive adhesive sheet, wherein the layer B is disposed in direct contact with the rear surface of the layer A. The method of claim 7,
The thickness of the layer B is 20 μm or more, the pressure-sensitive adhesive sheet. The method of claim 7,
The thickness of the layer A is 5 µm or more and 50 µm or less. The method according to claim 1 or 2,
The adhesive sheet having the water peeling force (N2) of 3.0 N/10 mm or less. A member with an adhesive sheet comprising the adhesive sheet according to claim 1 or 2 and a member bonded to the one surface of the adhesive layer. The method of claim 12,
The member has an adhesive sheet attachment member having a contact angle of 50 degrees or less with respect to distilled water on a surface in contact with the adhesive layer. As a peeling method of the adhesive sheet affixed to an adherend,
The adhesive sheet is the adhesive sheet according to claim 1 or 2,
In a state in which an aqueous liquid exists at the interface between the adherend and the adhesive sheet in the peeling wire of the adhesive sheet from the adherend, the aqueous liquid enters the interface by following the movement of the peeling wire. A peeling method comprising a water peeling step of peeling the adhesive sheet from the adherend while making it. The method of claim 14,
A peeling method in which the peeling wire is moved at a speed of 10 mm/min or more in the water peeling process. The step of peeling the adhesive sheet from the member to be adhered by the peeling method according to claim 14, and
A method for producing a member with an adhesive sheet, comprising a step of affixing an adhesive sheet separate from the peeled adhesive sheet to the member from which the adhesive sheet has been peeled off. delete delete delete delete

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